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View Full Version : More hints and tips, but more like 'musings'



arthurking83
03-02-2009, 4:01am
OK. sorry folks, for the boring topics and subjects.. but I'm bored and I needed to do something constructive.

Recently there have been some questions asked about sharpness and so forth on a fast prime lens, and I'm just posting my FYI and results on a few little tests I did.

Firstly, one thing you shouldn't expect is super sharp images at 1/6s and ISO1600 on an old tech camera, like the D70s.

I took a series of three frames at '3fps' which is not exactly accurate because at 1/6th it takes longer to take those three frames. Can't remember the exact shutter speed where 3fps actually kicks in, but that's not the point. We'll just call it 3fps, as continuous shooting mode may be confused with AF-C which is Auto Focus continuous mode.. two distinct and different features.

100% crops.
1.
http://www.ausphotography.net.au/staff/AK83/DSC_8301_100%25crop.jpg

2.
http://www.ausphotography.net.au/staff/AK83/DSC_8302_100%25crop.jpg

3.
there's no point in posting frame three, as it's only worse than frame one, and we're trying to save bandwidth here :D ..trust in me that it's worse, and not worth posting.

But what is relevant here is that focus was achieved and sharpness was alos much more than acceptable.. remarkable even, considering that the image was taken at ISO 1600 on a D70s!! that's right.. zero noise reduction by me, only what the camera had to offer(to CaptureNX) with which all I did was to crop. No WB adjustment... nuth'n!

D70s still has a lot of life left in it's future... going by #2.. and with minimal NR in PP.. it can come up looking a treat :D

To get that one image though I had to shoot 3fps, with the reasoning that 1/6 at 50mm was not going to yield a sharp shot.. so I used the SIN principle. Safety In Numbers.
Shoot more frames and hope for the best. Other call it spray and pray(I think that makes SAP??.... I prefer SIN ;))

OK.. if I post that #2 image only, it makes me look kind'a good.. almost as if I know what I'm doing.. but the reality is I don't.
I should have used a tripod for a better keeper rate, but once again, that's not the point. It's digital, and it costs nothing to delete a bad image.

I regularly shoot '3fps' and usually for exposure bracketing. I want to get a shot and move on. Usually I do know what part of a scene, I want to expose for, so this helps me stay dynamic and find greener pastures to settle on.. I'm happy and it works for me.

image #2 not exactly spot on sharp where it was supposed to be.. focus was set to the START button, but the Z button is sharper.
This can be normal, for many reasons.
Field curvature, slightly back/front focused lens operator movement camer AF misalignment.. etc, etc Some of the topics have already ben talked about in other threads, so it's time to show how much it actually means.
I could process more sharpness and contrast into that #2 shot and it would be easily printable in a large format.

Another reason you don;t normally hear too much about is the actual alignment of the focus lines within the actual focus area. The (central)focus area usually has two unseen lines that form a cross section to actually see the contrast required so that AF can be acquired. AF is simply seeing tow parts of the image and determining the contrast between them. Some AF systems are better than others, and so forth, and the more pro bodies have more cross section sensors over a wide area. From memory the D30 has 15 of them(over 51 points) whereas the D90 has one in the center. D300 wil therefore have a better AF system, where those other 14 points will help achieve focus over a wider area of the frame.
(you can also substitute Nikon cameras for any other brand.. but my knowledge of the topic is limited to Nikon cameras.)

Problem is that the tolerances in that AF area are very small, and the actual positioning of those cross hatch lines can be different in all bodies of a similar camera model. So it may be quite possible that no D300 or D3 will have exactly the same crosshatch positioning in any one particular AF area.
These cross hatches see in two different planes.
The vertical line detects the difference in horizontal contrast, while the horizontal line detects the contrast in a vertical plane. This is quite important as it affects how accurate your AF system is going to be. It's all about camera body tolerances, as mentioned in Kiwi's thread on back/front focusing (http://www.ausphotography.net.au/staff/AK83/DSC_8302_100%25crop.jpg).
as that article in question says the tolerances in one body is going to be different in another(and there are other tolerance differences to be aware of too!) so that it all gets multiplied to the point where one lens works perfectly on one body but not another.. then you get arguments by FLAO's :D like this is ****e over Nah!.... is awesome dude

Some more on these crosshatch lines within your AF area can be found ...
<insert link here when I find it>

OK.. what does it all mean.
Recently I sold a lens. A very nice lens that DID backfocus for me at the long end of the focal length. FACT!!
It did that very consistently BUT only at close focus distances.
I can't state that more clearly, and I can post many boring images if the naysayers can't believe the fact that lenses can backfocus.(problem is that I may have deleted the relevant boring photos due to their extremely boring nature! So try not to call me on that bluff :D)
That was the problem because at longer distances the lens was perfect, which renders micro AF adjustment features pretty useless for the majority of photographers(that tend to use zooms!) set the AF adjustment for xxx focla length, and xx focal length is affected too! BUT focal length xxx now front focuses at longer distances.. so the feature actually became more annoying that helpful.. remember I have many photos to prove that :p

So how do I know it backfocused? because Live View and my tripod and manfrotto RC5 plate helped me measure it. Easily and consistently.(it was about 2cm at 200mm f/2.8 and about just under 2meters subject distance!)
Do the DOF calculations and you'll soon realise that it was very unimportant part of using the 80-200mm lens.. So I did what came naturally, and ignored it for the most part :th3:
It was not a relevant issue to worry about. Usually you'll be shooting 200mm on one of these types of lenses at a minimum 5m or so, and most likely more.

Anyhow.... the answer was to sell the lens!.... Why?
Because someone asked if they could buy it. I was more than happy to compensate for those issues and it was rather easy to do... shoot at..... you guessed it... at 3fps :D
It works.. I used to do it all the time, as the focal length in question was quite hard to shoot with only 1 single frame anyhow. And surprisingly it compensated for my unsteadiness, fore/aft movement(which I'm sure we all have, unless we are quite deceased :action3: ) or on a tripod or whatever.... so the answer is 3fps.
Just have to figure out what the question was supposed to be :p

THEN!! (yes there's more) I had the opportunity to play with a Benro tripod and ballhead.

:th3:

If you had any doubts as to the quality of such name brands... don't!
It may not be a Gitzo or RRMarflippinottoS... but it sure feels bloody solid.
J3 ballhead was a remarkable piece of engineering ... FOR THE PRICE.
less than $300 from memory, and well worth more than that. Operation is smooth and locking down is kind of akin to granite.. large slabs of the stuff.
For approximately the price of a Manfrotto 488.. you get a massive ball(makes a huge difference to the solidity of the device). and we hung a largish lens off the body and it was just solid.

If you were thinking of getting a benro... just do it, and get the J3 head.. it's big, but not massive, as the Manfrotto MGR468 is.
My only concern was the benro plate that attached to the camera body. it was sculptured to suit a particular camera model, but from memory you can get a standard flat plate to suit. I'd get one of them, or a better quality Arca Swiss plate from the likes of RRS/Markins/whoever else.

(ps I personally prefer the manfrotto RC5 plate! :confused:)

Anyhow, I should have brought the 300/2.8 to test as well... but we'll organise that for another day :)
I've hung a camera with a largish lens off my 488(quite used) and it droops. It droops so much that sometimes it doesn't stop! :action3:
I've done it on my D300 and 468MGR ballhead and it drops a little from where you actually compose.
This J3 head is much more solid and it didn't appear to recompose for you at all.
When I say camera and largish lens, I'm talking about a xx-xxx f/2.8 hanging way out front off the body, rather than the normally accepted practise of using the lenses tripod mount/collar!
Hanging a large lens off a camera using the tripod collar is standard fare operation and doesn't stress a ballhead. As I've said.. if you want value for money that J3 is great.
I'll be getting one soon too :th3:

Tripod was the 298 carbon, and it was nice and light weight, and as solid as any Gitzo or Manfrotto as I've ever seen. But I haven't seen the newer 25xx 35xx Systematic tripods in Aust yet.
The legs were kind of expensive sounding, but the whole shebang was very lightweight.. very very light weight!
I like my Manfrotto 458B legs, simply because they are so quick to use. SIMPLE as that!

Now for the vast majority of people all that may be meaningless.. but if you have a kind heavy long focal length lens, my 80-200mm, 500mm, 300mm(with TC's) all showed up the shortcomings of an inadequate ballhead.. which was only compensated for with Mirror LockUp on the camera body.
And at faster shutter speeds you may not see that too, but you can't always use fast shutter speeds. Sometimes 1/6s is the norm, and it becomes clearly obvious.

Read that as: if you use a tripod for landscapes at 10mm you can easily disregard everything I've said about tripods here.... so too bad :p
But of you are in the market for a tripod and head, why not get the best value for money.. just in case?

All this is relevant because it comes back to 3fps. I can get acceptably sharp shots using my 500mirror and 1/60s on my currently almost inadequate tripod/head.. because I use 3fps.. so there are always workarounds... or mirror lockup or exposure delay or whatever.

if you shoot birds @ 600mm!.... you too can also disregard everything I've said here :D.. go to the back of the queue :action:

These musings only really apply to slow shutter speeds and long and/or heavy lenses.

SO!! what does all this mean? :confused013

I sold my beloved 80-200mm f/2.8! Arrrggghhh! :eek:
Never mind. It went to a very good home, and I think(I hope) the new owner wil post some cool pics taken with it soon... but not of chooks! :p

SO!! why the rant? .. because of doing the smart thing, and waiting to determine the correct next lens purchase.. I kind'a detoured into the heart of Melbourne's camera precinct.. just to try a new one on for size.. and I (inevitably! :D) caved in and bought a new one... :action3:
NO!! actually that should have been a .... :action:

:D

OK.. so we finally get to the last section of my late night/early morning ramblefest! :rolleyes:
I bet you're all thinking.. 'phew'!!.. we can stop reading now.. y'all a bunch of bird loving, short focal length, fast shutter speeds(and I bet high ISO) freaks, I reckon! :love0:
So.. we get to the tamron 18-270mm :th3:

Great lens, if you can get it for approximately $820, like the chap in the city told me he'd sell it for. If he doesn't and you want it.. we can go in together, and I'll remind him of that price.
VC is good, 270mm is great for a consumer grade superzoom).
Maybe not for cropping to 100% and then posting.. but at 50% it's more than adequate. (once again.. I have the pictures to prove it :p)

Doh!
50% crop view.
http://www.ausphotography.net.au/staff/AK83/DSE_0424_50%25.jpg

100% crop view
http://www.ausphotography.net.au/staff/AK83/DSE_0424_100%25.jpg

Now they may look unremarkable.. but in fact they are quite good.. very good I say because they are simply snaps taken from a store for testing purposes of a subject about 100m away with the lens totally wide open @ f/6.3. At f/8 maybe you could eke out a little more sharpness, or add some contrast and improve them a little.
At full view you'd be saying .. hey not bad for a do it all zoom lens. Remember it's also taken at 1/125s and at 270mm! VC helps, but is not the perfect answer to all the problems either.. it just works great(as does VR).

Well... I told the man at the store.. hey not too bad.. I'll get one of those!.... (one day soon :D) but not today.. I got something else :crzy:

Anyhow.. I know my son would enjoy the 18-270mm, as would have I on the Sat Melb meet. Just one lens( per body) and two bodies the other lens would have been the 50/1.4.
Would have saved my back.... but then again I would have felt only half complete.

OK. it's time to go to bed(it's 4AM! :eek:)

Hope you enjoyed reading this 12 part mini series of all things great and FLAO(see Kiwi's thread!!). Hope you got some small tidbit of valuable information out of it?


ps. I hope to be able to find that link to the AF/crosshatch webpage that helps to explain your AF system a little better