A new birding lens for my Nikon.

[Cage]

You must have the original version as I looked at the weight of the Mk II version which is considerably lighter at 3.2kg's.

I think I'll need a couple of weeks on the 5kg dumbells before I try hand-holding again.

[Morgo]

All that said, in my brief experience with the Sigma, I found it rather more difficult to hand-hold than I expected. (Ditto the Canon 200-400/4.) Was this (a) something to do with the weight distribution, I wondered? Or was it (b) to do with the more restricted choice of gripping points as the two zooms include both focus and zoom rings where the prime only needs a focus ring? Or (c) simply that I've owned the 500 for many years and am not used to holding the zooms? I'm inclined to suspect that (c) is the most important factor, but not the only one.

Most likely (B) is getting in there as well.
I find my 300 2.8 IS II and even my 600 F4 IS are easy to hold (the 600 for short times) due to not needing to manipulate a zoom ring. My Canon 200-400 is easy to hold weight wise but sometimes holding it and operating the zoom can be a little awkward.

[Cage]

Can anyone with a Sigma with OS tell me how to know when the OS is working? With my Tamron it is obvious when the VR kicks in as the focus point indicator-stabilises, but nothing shows in the viewfinder, no beeps or motor noise with the Sigma.

And I've been thinking about some sort of stabilisation for hand-holding, and was wondering if one of those belts that game fishos use might help by putting the foot of a monopod in it.

[arthurking83]

Sorry been MIA, too much work, no time to play!

Anyhow, the first thing I was going to recommend, is that you don't connect the dock thing via USB3 .. but you've beating me to the punch .. same experience here!

.... Dunno whether to use the dock or do it in-camera.

Remember the old days, how you used to make fun of my fanboism for the Sigma lens dock thing(and now Tamron doing same .. and hating Nikon for not doing same).
Always use the dock.
If you have PC(or other device) connectivity to the camera and can do realtime live view feed, it's 'more accurate' than doing it by hand, on a tripod, using your finger to AF, in controlled conditions, indoors, and also outdoors unless you use a specific target type .. etc.

Anyhow, the reason for my dislike of non connectable lenses, goes way back.
The good old Nikon 80-200/2.8 AF-D specifically, and less bothersome but similarly afflicted Tamron 28-75/2.8 lenses.
They both gave me grief on various cameras. Less noticeable on the D70s, and more notable on the D300.
The Tamrons problem was the very slight amount of play in the gear/screw slot for the AF drive. It misfocused but only at 75mm, only at f/8 did the DOF mask the misfocus .. but who buys an f/2.8 lens to use at f/8!
Easy fix .. so for me the misfocus on the old Tammy may not have been Tamrons fault completely.

But the Nikon 80-200/2.8 AF-D .. royal pain in the posterior for me. So much so that it's the only lens I've ever sold(and probably ever will).
Misfocus was at 200mm and very obvious. Problem was I couldn't over ride it like I could on the Tammy lens.
All the experts say go with the name brand, first party lenses all work, you won't have issues .. etc, etc. .. bs, bs .. I can tell 'ya very differently.

In camera AF adjustment is OK, only in very specific conditions.
1. it's not a zoom, and that obviously means it's a prime lens. and 2. if it's a prime lens, make sure you don't go using a similar model prime lens if you have one already set in AF adjustment memory in the camera. The other one will also be AF adjusted and may not need it!

So there 'ya have it .. why I have a massive preference for connectable lenses .. plus add into the equation Nikon's recent woes with some of their lenses .. and the trouble that some owners would have had to go through to get a lens to work, when it should never have not worked to begin with! Having access to stuff like USB docks that allow lens adjustment ability never hurt anyone!

Anyhow, if you adjust the focus tweak you may require in camera, it'll throw out the focus for all focal lengths and focus distances on that lens.
It's almost a dead cert that you don't need the same adjustment for the entire lens, and the software has been made to cater for this point.

When you get into the Sigma software, and get to the Customisation tab you'll see that it's adjustable for set focal lengths(150, 250, 400, and 600mm) and for each of those focal lengths you have 4 different focus distance settings to allow you to adjust for.

I've tested all settings, and have found no tweaks needed, but I only did it quickly.
I used a picket fence post outdoors at the required shorted distances, and had to use a distant house roof(chimney) for the infinity test.

Unless you have a lens cal type angled confabulation to play with for AF accuracy, I suggest you don't use an angled ruler to do the test with. They're not as accurate as you think they are.

Back to the comment re the ability to connect the camera to a device that allows you to view a remote live view feed.
I used my little tablet using ControlMyNikon software, which allows you to adjust focus in micro minute steps(as long as it's an AFS type lens).
Much finer adjustment step ability than the camera can actually allow you to play with. That's for the software .. dunno which other software allows you to do the same.

So using the remote software, focus camera as per normal on a tripod, using thumb(AF-On) activated method .. view liveview image and assess the image quality.
Then with ControlMyNikon software, adjust focus forward and backward to see if I could make it more focused.

Like I said, using that method .. my Sport was pretty much spot on as it was.

As for OS. Go into Customisation and look for [Customisation Mode Setting]. Click.
(this may sound convoluted .. and it kind'a is!!)
Now you get to buttons C1 and C2. They both correspond to the lower button on the side of the lens. The other setting for that button is OFF. Note this button.

When you make any adjustments to the C1/C2 operation modes, you then have to use that C1/C2 setting on the lens.
So if you adjust anything in one of the custom modes, then it only works on the lens if you set it to the appropriate custom value. If you have it at OFF, then obviously the custom settings you made using the software isn't applied to the lens.

eg. say you want the dynamic OS mode which has a more aggressive OS viewfinder operation, but you want to leave AF speed as normal, and focus limiter(not AF adjustment!) as normal too.
So go to C1 and you'll see the three adjustment tabs, only use the OS settign tab and set it to dynamic.
C1 will now have a dynamic OS setting, and AF speed and AF limiter are not adjusted(it says so next to the respective button if it's not set) .. use C1 for that personal tweak.

But if you wanted slightly twitchier quicker focus speed, but with a hint of possible inaccuracy, then for C2, you could just adjust the AF speed to fast AF priority, also set OS to dynamic and if you want, set focus limiter to '5m to infinity'.

so now, C2 mode is a birding mode, I can't imagine a bird closer than 5m, but could be at infinity .. so AF is less likely to hunt in low light.
OS is in the 'best mode', and AF speed is as quick as the lens gets for 'ya.
But C1 mode is only for the more aggressive dynamic OS feature, and AF speed will be normal and AF limiter is from MFD to infinity.

**Very important to note** It's not obvious for first timers, but if you tweak anything in this area you MUST hit the [Rewriting] button at the lower edge of the screen. If not, all the settigns you tweaked won't be written to the lens.

Personal opinion: OS works. It is different to other stabilisations in lenses. It's less aggressive, less obvious in the viewfinder. BUT you should see the small sidestep when the OS activates when the camera meter is activated, or AF or whatever.
I'm not seeing a lot of difference in viewfinder between standard OS and dynamic modes, but there is an extremely slight difference in the way it snaps to initiate OS.
I feel there is a difference between fastest AF mode and normal. less so between normal and smooth tho.
I've never found any need to limit AF limiter ability. Lens generally finds focus as accurately as I've seen in any other lens I've used.
You can fool it of course, but then again I've seen the Nikon 70-200/2.8 fooled too!
Focus system is at least 95% workable/usable.

The one and only thing I hate about the lens is the silly lens hood locking bolt thing .. just silly, where a spring loaded tab pull to release, release to lock system would have been much nicer for what feels like a very high quality finish.

[Tannin]

Remember the old days, how you used to make fun of my fanboism for the Sigma lens dock thing(and now Tannin doing same .. )

How do I love thee? Let me count the ways. I have owned ... er

,,,, OK, I'm back. Took me a while to make a list, and I may have forgotten one or two.

But near as I can count, overt the last dozen years, I have owned 17 SLR lenses and 12 Canon DSLRs. Cross out three of the lenses if you like because one of them is manual focus, and two of them were Tokina rather than Canon. Out of those 12 cameras and 14 Canon auto-focus lenses, used in pretty much every combination. how many have needed adjustment via a dock, or indeed adjustment of any kind?

Precisely zero.


(Tannin reads Arthur's post a little more carefully ....

Remember the old days, how you used to make fun of my fanboism for the Sigma lens dock thing(and now Tamron doing same .. )

Oh. Sorry 'bout that. As you were then.

[Cage]

Sorry been MIA, too much work, no time to play!

Anyhow, the first thing I was going to recommend, is that you don't connect the dock thing via USB3 .. but you've beating me to the punch .. same experience here!

Remember the old days, how you used to make fun of my fanboism for the Sigma lens dock thing(and now Tamron doing same .. and hating Nikon for not doing same).
Always use the dock.

If you have PC(or other device) connectivity to the camera and can do realtime live view feed, it's 'more accurate' than doing it by hand, on a tripod, using your finger to AF, in controlled conditions, indoors, and also outdoors unless you use a specific target type .. etc.

When you get into the Sigma software, and get to the Customisation tab you'll see that it's adjustable for set focal lengths(150, 250, 400, and 600mm) and for each of those focal lengths you have 4 different focus distance settings to allow you to adjust for.

Back to the comment re the ability to connect the camera to a device that allows you to view a remote live view feed.
I used my little tablet using ControlMyNikon software, which allows you to adjust focus in micro minute steps(as long as it's an AFS type lens).
Much finer adjustment step ability than the camera can actually allow you to play with. That's for the software .. dunno which other software allows you to do the same.

So using the remote software, focus camera as per normal on a tripod, using thumb(AF-On) activated method .. view liveview image and assess the image quality.
Then with ControlMyNikon software, adjust focus forward and backward to see if I could make it more focused.

Like I said, using that method .. my Sport was pretty much spot on as it was.

As for OS. Go into Customisation and look for [Customisation Mode Setting]. Click.
(this may sound convoluted .. and it kind'a is!!)
Now you get to buttons C1 and C2. They both correspond to the lower button on the side of the lens. The other setting for that button is OFF. Note this button.

When you make any adjustments to the C1/C2 operation modes, you then have to use that C1/C2 setting on the lens.
So if you adjust anything in one of the custom modes, then it only works on the lens if you set it to the appropriate custom value. If you have it at OFF, then obviously the custom settings you made using the software isn't applied to the lens.

eg. say you want the dynamic OS mode which has a more aggressive OS viewfinder operation, but you want to leave AF speed as normal, and focus limiter(not AF adjustment!) as normal too.
So go to C1 and you'll see the three adjustment tabs, only use the OS settign tab and set it to dynamic.
C1 will now have a dynamic OS setting, and AF speed and AF limiter are not adjusted(it says so next to the respective button if it's not set) .. use C1 for that personal tweak.

But if you wanted slightly twitchier quicker focus speed, but with a hint of possible inaccuracy, then for C2, you could just adjust the AF speed to fast AF priority, also set OS to dynamic and if you want, set focus limiter to '5m to infinity'.

so now, C2 mode is a birding mode, I can't imagine a bird closer than 5m, but could be at infinity .. so AF is less likely to hunt in low light.
OS is in the 'best mode', and AF speed is as quick as the lens gets for 'ya.
But C1 mode is only for the more aggressive dynamic OS feature, and AF speed will be normal and AF limiter is from MFD to infinity.

**Very important to note** It's not obvious for first timers, but if you tweak anything in this area you MUST hit the [Rewriting] button at the lower edge of the screen. If not, all the settigns you tweaked won't be written to the lens.

Personal opinion: OS works. It is different to other stabilisations in lenses. It's less aggressive, less obvious in the viewfinder. BUT you should see the small sidestep when the OS activates when the camera meter is activated, or AF or whatever.
I'm not seeing a lot of difference in viewfinder between standard OS and dynamic modes, but there is an extremely slight difference in the way it snaps to initiate OS.
I feel there is a difference between fastest AF mode and normal. less so between normal and smooth tho.
I've never found any need to limit AF limiter ability. Lens generally finds focus as accurately as I've seen in any other lens I've used.
You can fool it of course, but then again I've seen the Nikon 70-200/2.8 fooled too!
Focus system is at least 95% workable/usable.

The one and only thing I hate about the lens is the silly lens hood locking bolt thing .. just silly, where a spring loaded tab pull to release, release to lock system would have been much nicer for what feels like a very high quality finish.

Thank you Uncle Arthur, once again, for your thoughtful and comprehensive reply.

As said above, somewhere, the lens was front focusing, so I did the in-camera micro adjustment, and the results from about 100 shots were, to say the least, somewhat underwhelming. OK, it was late afternoon and I was chasing the light, but the below post pretty much sums up what I got. Oh, and on the odd occasion I did notice the OS kick-in.

The Evil Wren.jpg

Most shots were OOF, most likely due to my set-up and technique, but also probably due to the lens not being set-up correctly.

It will probably take a day or so for my tired old brain to suss out all the salient bits in your post, but it is obvious that the dock is the way to go. And yes, I gave you a rev-up about your 'dock love', but I'll admit that it was one of the reasons that I went for the Sport, along with Brad Hill and TDP.

Thanks again for informative reply.

PS: I have no doubt that when I get it sorted, the lens will be a weapon.

PPS: @ Tony , docks rule, OK.

[arthurking83]

While I haven't got as many AF lenses as you have had over the years, I still have enough to have 'similar' experiences.
But, some can slip through the net. ie. count yourself lucky!

But in all seriousness, there will be in any system of mechanically connected parts, some inherent tolerances that need to be taken into account.
They have too, otherwise they would all be bespoke items that can only perfectly fit selected companion parts with zero tolerance between those parts.
It's this built in tolerance that allows the ability for those parts to become interchangeable. Tolerance = inaccuracy. Inaccuracy = errors. Errors(in focusing terms) = misfocus.

It's commonly claimed, and written by many professionals and other well known photography personalities that they have multiple copies of lens A and one has 5 microns of backfocus and another has 4 microns of front focus.
Look hard enough and under the right circumstances and you'll find it too.

But .. more to the point .. Nikon have of recent times displayed why accessories like lens connecting devices can play a significant part in building more honest relationships with the customers!
200-500/5.6 and before that, the 300/4 PF lens both had to have firmware updates for some lenses from early batches.

Now as a customer, I've just spent $2k on a lens, I may have driven an hour to locate a reliable/reputable retailer, or may have spent upwards of $50-100 for insured freight to get this lens into my eager hands.
Then to find out that it needs to go back to Nikon to get a firmware update.
As far as I remember, Nikon never compensated anyone for their freight costs to get their lenses to the repair facility, only the cost of getting it back to the customer.
Otherwise it'd have been another hour wasted getting to Mr Reliable/Reputable retailer in the big smoke, having parking hassles, cost of fuel, burden of having to deal with big smoke .. etc.
All this having just spent $2K to get the so called reputable, first party, known to not cause issues, big brand, gear!

And on the other hand, the less reputable manufacturers allow this exact same firmware update to be done from the comfort of your own PC connected environment... be that in your own warm cosy study, or in the polluted big smoke, sipping on a latte at the cafe using their wifi, right next door to the reputable/reliable retailer.

ps. I tried to count haow many lenses I have, to compare your figures, and I kind'a lost count .. actually lost interest, which lead to loss of train of thought, which lead to loss of the last number I had to remember when I pointed to another lens .. so I dunno about 10-12 AF lenses, on 3 bodies.

D70s not very obvious to take notice of focus errors due to it's low resolution sensor .. but the 80-200/2.8 was noticeable. Less so the Tammy(28-75mm).
More obvious on the D300 tho.
I think I did try to look for it on the D800(with the Tammy 28-75), but I never really cared much about if it was there or not.
The larger camera body of the D800E made the lens nicer to use for some reason. D300 is a large-ish body, but the slightly larger D800 body type just made it the 28-75mm nicer somehow.
Nikon 80-200 was long gone by the time the D800 came along, and if I still had it, I'd have scrutinised it at 10x magnification.

I reckon, if I look hard enough I may be able to find a reason to set the Sigma with a -1(out of 20) in one of selected focusing slots.

[basketballfreak6]

hey Kev congrats on getting the lens! a few tips from me...

i find it much easier to use the lens as a push/pull lens, actually feels surprisingly intuitive that way, i actually find it hard to use it as a standard twist zoom i think due to the fact that the zoom ring is a bit stiff but probably more due to the fact that there is a lot of glass to move, so my hand is pretty much sitting on the lens hood, feels very comfortable for me using it that way

in terms of OS you can change OS behaviour using the dock and program can set it so you can see the OS working via viewfinder (pretty sure)

i took it out yesterday myself for the first time in a long time and is still impressed at its performance, it's up there with my best lenses accuracy wise (and i own canon's 24-70II and 70-200II) everything just hits and also how sharp it is...i can happily do some pretty heavy cropping

[Cage]

hey Kev congrats on getting the lens! a few tips from me...

i find it much easier to use the lens as a push/pull lens, actually feels surprisingly intuitive that way, i actually find it hard to use it as a standard twist zoom i think due to the fact that the zoom ring is a bit stiff but probably more due to the fact that there is a lot of glass to move, so my hand is pretty much sitting on the lens hood, feels very comfortable for me using it that way

in terms of OS you can change OS behaviour using the dock and program can set it so you can see the OS working via viewfinder (pretty sure)

i took it out yesterday myself for the first time in a long time and is still impressed at its performance, it's up there with my best lenses accuracy wise (and i own canon's 24-70II and 70-200II) everything just hits and also how sharp it is...i can happily do some pretty heavy cropping

Cheers Tony,

I've been working on the auto-focus fine tuning, all sixteen options, as my lens was front focusing on the D7200 to the extent that small birds were all OOF and I thought I had got a dud. Feeling better now and I am starting too see some results.

[Cage]

While working on the auto-focus tuning this Pee Wee dropped in.


Pee Wee with Sigma 150-600 Sport by @Cage, on Flickr


Pic is nothing special but I was pleased with the detail in the black plumage on the breast. This lens seems like a good match for the D7200.

This was shot off a tripod with the OS enabled, and I'm now seeing the OS kick in, probably because it can now find a focus point. The lens was front-focusing maybe about 45mm, so it was missing focus on small birds completely.

I've set the in-camera micro-focus back to zero and am working my way through the various focal lengths with the dock.

So Artie, I wont stir you for your 'dock ' anymore because the bloody thing works, and works well.

[arthurking83]

.....

So Artie, I wont stir you for your 'dock ' anymore because the bloody thing works, and works well.

So, I'm going to sell mine, and stir you about it!

ps. for focus testing, best way I found was to use batteries. (if I find the pics, I'll post them).
Basically, get about 5 batteries(AA or AAA) line them up across so that there is about 1 battery width space between each. Then arrange them fore/aft in a V pattern too.
Space them so that the back edge of one of the leading batteries is on the same plane as the front surface of the further back battery.
The reason I use 5 batteries is that I focus on the middle one and have four batteries either side not only watchign for back(or front) focusing accuracy, but also tilted film plane issues(ie. I didn't line the camera up well enough) and or lens build issues with respect to focus plane tilting.

           O   O
            O O
             O


             _
           CAMERA

O's are the batteries, _ is the camera.
That setup is for testing backfocus, if testing for front focus the V shape of the batteries lineup is reversed.
If your lens is backfocusing, and you always focus using the centre point on the central subject, then the rear batteries will come into focus better.
Note that one may be, and the other may not be. All this usually means is that the camera(film plane) isn't square to the V shape of the batteries.

I used AAs as they're bigger and then you can move further back and still maintain the focus point area within that single centre battery.
It's important to have that focus area box only covering the that one battery and nothing else or any other battery.

To explain why using the angled ruler for focus accuracy testing is going to max out the available space on the AP server!

If this is vitally important to you, a lens cal type focus accuracy testing thingy is probably a good thing to have, otherwise make your own up.
There's nothing wrong with the angled ruler itself, just that tryign to focus on it is a random guess at best(due to the way that the focus box is designed).
So with a couple of pieces of some solid material(eg. ply, very strong cardboard, masonite, or whatever) .. you'd have the ruler only as the measuring device but the subject target HAS to be square on to the camera/lens.

I occasionally have random thoughts on on cobbling up a home made focus testing doodad with some random materials I have here and there, but the battery test targets have worked well in the past, and currently have no lens focus issues.
Although my testing of my Sport was very quick and crude(not using the batteries).

With my 80-200/2.8 at 200mm and about 4-5m distance I found that I focused on the front battery, and the lens focused on the second row batteries. Setting a 5-10 value in camera forward fixed that up perfectly.
Only problem was it totally stuffed all other focal lengths, and .. it stuffed 200mm beyond about 20-ish or so meters.
If the camera allowed varying adjustment values based on focal length for zooms, and focus distances for all lens types, then it'd be as good as the tweaking ability of the Sigma(and I assume Tamron) docks + software.

BUT NOTE!! if you do adjust for your D7500, that doesn't mean it will be the same for another camera, even if it's another D7500!

[Cage]

Cheers Arthur.

I've been using the battery method for years but I use them in a straight line at 45° to the camera, a battery width apart.

However I've gone high tech and downloaded and printed a test chart from the internet.

Focus Chart.jpg

Strangely enough, or not, the increments backward or forward of the focus point on the test chart pretty much correspond to the increments of adjustment on the Optimiser Pro. Go figure.

If you look at my post in 'Birds' I think you'll agree that I'm making some progress.

PS: I was pondering on the possibility of using the dock on a different camera and wondered that if you used a different focal length to those already set, the program would just set that adjustment as per usual, but all your other pre-sets would probably be out for that camera..

PPS: If Sigma are really, really smart they will do the software for various cameras and allow your lens to recognise which camera it is on and adjust as necessary.

[arthurking83]

Warning!! long post may ensue from this point onwards!

....

However I've gone high tech and downloaded and printed a test chart from the internet.

....

That test chart is OK to use, except for one thing.
The black bar where you focus at is known to cause focusing anomalies.
That is, you can't be 100% sure that the camera is actually focusing at the correct point on the line, even tho it should focus on the wording that describes to focus along that line.

If you have the image of that printout in electronic form as an easy to edit image file, what I'd reckon you should do with it is to replace the thick black line with the wording and add a series of lines using the + = and \ / symbols instead.
Those symbols give the focusing system a better chance of focusing exactly the same way every time(apparently).

Ideally what you'd want is a small cutout in the centre of that focus line and slot in another target to focus on, making sure that the slotted in target is at 45° to the plane of the ruler and on the same plane as the camera/lens combo.

That focus test target was originally designed for testing focus change due to aperture adjustment .. ie. focus shift. But in those tests you were so much measuring AF accuracy, just measuring how focus changed when only the aperture is stopped down.

Overall, nothing wrong in a general sense in using a similar layout to measure focus accuracy, as long as you fully understand the tech implications behind what can go wrong.
But a small cutout, print something like a Siemens Star on a bit of paper, stick that to a bit of cardboard that gets slotted into the cutout and you have saved yourself a couple of hundred bucks on a lenscal!

[Cage]

Good 'onya, just when I thought I had it sussed you throw a spanner in the works.

I looked at the Siemens Stars, briefly, because the moire was making my eyes roll around like poker machine reels. Dunno' whether all that moire would help or hinder focus.

I don't really understand what the problem is with the chart that I'm using (and no further explanation required ) because if the focus point wanders off along the horizontal plane that shouldn't be a problem because I'm looking for variance on the vertical plane, and if it mis-focuses on the vertical plane it would be such a small deviance that it should not cause much of an issue for my usage.

Anyhow, I've found this Siemens Star Chart with a less moire inducing centre.


Siemens_star Chart.jpg


What do you think?

[arthurking83]

....

I don't really understand what the problem is with the chart that I'm using (and no further explanation required ) because if the focus point wanders off along the horizontal plane that shouldn't be a problem because I'm looking for variance on the vertical plane, and if it mis-focuses on the vertical plane it would be such a small deviance that it should not cause much of an issue for my usage.

....

That's the little eye straining tacker!
Apparently they are 100% hit rate on AF systems.

I had to look up one of my old reply on how AF systems are set up, but it's an old thread(not mine) and I can't locate it.

Think of the focus point as this [+] some are double cross points [#].
In theory they're supposed to be lined up exactly like that, but what I've read is that in practice they almost never are.
So the cross points may be lined up either a bit left/right or vertically higher/lower relative to the square, and all you see is the square.
So, lets say you have some lens to camera tolerance issue, which varies for each camera lens combo, AND you're focus cross points are wayyyy off in terms of where they're supposed to be in the focus square.
So while you're trying to line up the focus square on the thick black line, the + and or # focus system is scrambling to locate something definite to differentiate contrast on, it may well be way off the point that you've aimed at too, and the camera-lens tolerance is also pushing the boundaries of acceptable focus acquisition times. And all this has to be done in micro seconds or else consumer A is going to complain on every forum that Lens X is crap and Camera Y can't focus!

If you understand how the focus system works too it helps to visualise the process as a whole.

there are vertical | focus lines, that look, and adjust, for horizontal - contrasting areas.

That is, a straight vertical | type focus point type will struggle to focus on a verticallly oriented contrasting areas. But it easily locates and differentiates a horizontal contrast area.
The opposite is true of horizontal focus types, but you don't get them in AF systems on their own.
What you get is a stack of + and double + types(those # types) and then for the periphery AF types are all vertical | types.

An easy way to test this is to find a background with no contrasting elements at all. Something smooth and monotone all across. The camera will struggle to focus on it as there really is nothing of interest to focus on. But being 'a thing', you can focus on it as long as it's within focus distance range.
So to test the AF point types, get a hair, as in hair off your head, or something so minute and infintessimal that the focus system will struggle to see it. A hair is good, making sure it's dead straight, no curves.

Place it horizontal first on the background, and no matter which AF point type you use, the AF system will see something against the background of nothing(above).
The place it vertically, and the central + and or # type af points will still see the hair courtesy of the horizontal - component in the + and # pattern, but the vertical | type AF points at the periphery struggle to see this | pattern. They will be hit and miss, as I remember mostly miss.
If you move the camera left to right it can sense the differences at some points.

I remember the chap that had some the info on this topic used a hair to determine the location of the | lines within the [] af boxes on his D70s wayyy back when. They were way out there in terms of where you think they should be .. almost certainly not central to the AF square.

diagonal \ and / type lines usually work well as well as the hash symbol#. It gives the AF internals a chance to see something without any issues.

Back in the day, did you ever use an old SLR with a split prism type screen? If so do you remember the way the split prism used to work? The aerial image used to be divided into two halves and then would come together as you focused.
They were mostly horizontally split, so vertically oriented scenes would be easy to differentiate. But a horizontally oriented contrast scene would be hard to see come together using the same setup.

Hope that makes sense.

So the only problem with THAT particular focus chart is just that thick line focus area. You don't know if the camera has decided that the top black/white demarcation line is the focus point, or the lower one, or the lettering.
This is why I said, I'd remove that thick black line and replace it with those symbols.

ps. I used to have that file I think as a jpg, do you still have the file on your PC? I lost mine, but have a few other focus test types. If you have the file, can you somehow get a copy to me, or post the link to the site that you can download it from .. I wanna have a go at editing it.

[Cage]

You can find it here ....https://www.dpreview.com/forums/post/54034945

[arthurking83]

just edited it and removed the black line added a brick patterned line in place of it.

- - - Updated - - -

Had to find it eventually.

This is the thread I was referring too about the diagrams to show you how misaligned the focus spots can be

http://www.ausphotography.net.au/for...=focus+problem

[Cage]

The revamped test chart with Uncle Arthur's suggested focal point (I think). Seems to work OK as I'm getting pretty close to being happy with the auto-focus.

Test Chart.jpg

I've now checked auto-focus at 3m, minor adjustment, 6m, big adjustment, 10m and infinity with no adjustment. Hoping to get out tomorrow to test it all out in the wild.

[Mark L]

Use f/8 and just go and take photos of birds.

[Cage]

Use f/8 and just go and take photos of birds.

I dunno how your lens was when new but out of the box mine was front focusing about 80mm at 6 metres, enough to totally miss focus on a small bird.

It's a pain in the arse but I reckon the hassles in setting it up properly will be well worth it.