Big Siggy

[Fruengalli]

OK so my daughter has lent me a Sigma 150-500 hence some long range shots of late. Having trouble with surf shot focus using servo with lens IS enabled (800 iso 1000 sec or better).I seem to get sharper shots on one shot as opposed to servo.The manual says 1 second for IS to work so maybe its softening focus ???

[arthurking83]

OK, I don't have Canon, but many features found in one brand can be found in the other.

But this could be camera related too.

If you have a mid to high level camera, there could be a setting for when focusing when using servo mode(in Nikonspeak it's called continuous) .. that adjusts the speed of the servo focus mode.
This setting is generally used to set the delay speed, for when your intended subject is blocked by another subject, but in reality the camera doesn't know what is a subject and what is an interfering subject.

(usually) this setting is to adjust the speed of the delay of the focus system in trying to achieve focus.
Note that it's not to adjust the speed of the focusing system, but the delay in focusing.

Setting a long delay for this setting means that the focus system will wait a pre defined period before trying to achieve focus again, whereas setting a short delay(or off) means that the focus system will try to maintain focus quicker.

But note that this lens is noted for a not so fast focusing system. It's not the worst lens, I've ever tried, but it is a consumer level long lens, targetted towards folks with financial constraints!
My play with this lens was fairly brief, but I've had slower focusing lenses than this.
But, it did provide some pretty impressive results considering it's price tag!

If your camera doesn't have this servo delay setting, then there's not much that you can really do, as the focus speed is a lens related specification.

[Fruengalli]

My 5dII doesn't have the features you mention BUT after giving it some thought I think it was op error.Servo needs constant half press for constant focus & I was approaching shots as if it was single shot (tracking,half press,fire) so the lens had no chance. I've taken some more with a little more thought & they are much better.Thanks for the input anyway.Cheers

[arthurking83]

Aha!

Like I said .. no idea on anything Canon related.

BUT!! In saying that, I'm sure that a 5DII must surely have an AF-On button for focusing.

I suggest setting the camera up with the AF-On button for focusing

[Fruengalli]

Aha!

Like I said .. no idea on anything Canon related.

BUT!! In saying that, I'm sure that a 5DII must surely have an AF-On button for focusing.

I suggest setting the camera up with the AF-On button for focusing

I already have it set for focus lock..

[MarkChap]

Your 5D MkIII will have th efunctionality Arthur speaks of.
In the custom functions you will be able to set a priority for frame rate or focus, so after initial focus and first frame do you want the camera/lens combo to prioritise frame rate or focus.
You will also be able to adjust Servo focus sensativity, not sure where exactly it will be on a MkIII, but it will be there in the custom functions

[Fruengalli]

Your 5D MkIII will have th efunctionality Arthur speaks of.
In the custom functions you will be able to set a priority for frame rate or focus, so after initial focus and first frame do you want the camera/lens combo to prioritise frame rate or focus.
You will also be able to adjust Servo focus sensativity, not sure where exactly it will be on a MkIII, but it will be there in the custom functions

Thanks Mark but its "only" a 5DII

[MarkChap]

sorry bloke, misread the model

[arthurking83]

I already have it set for focus lock..

You've set your AF-On button for focus lock?

In that case, for these sorts of shooting genres, you're better off setting it to just focus(ie. on demand).

If focus lock does what I think it does, then when using the AF-On button for focusing, makes the AF-On button focus lock by default anyhow(I think).

eg. if you set focus lock onto a subject, this simply means that you' have focused, and now the camera can release the exposure, even if you recompose or alter the focus point.
(most cameras are set not to release, if focus isn't achieved).

With AF-On used for focusing, you (obviously) choose when to focus yourself .. so by not focusing again .. you still have locked focus to where you last reset it anyhow.

ie. basically same difference, just a different flavour ... AF-On is far more flexible. Many who also have switched to it, now swear by it and it's hard to go back.


Hope that all makes sense, if you try it and persevere a bit with it, I'm sure it will for you too.

[Fruengalli]

perhaps you should investigate canons before comment?

[arthurking83]

And exactly what will this achieve?

If you don't want assistance, it's usually better just to say so!

[Fruengalli]

And exactly what will this achieve?

If you don't want assistance, it's usually better just to say so!

Hmmm....seems my Friday night humor has got me in strife again.Probably should have had LOL at the end my comment.Note to self-No typing after 10 PM.But back to the AF on button-I normally work in one shot mode so I just find it easier for focus/recompose if I use focus lock as the option.Anyway cheers for the help.

[arthurking83]

Right.
So if you take the time to explain why 'focus lock' is important to you, then either I, or someone else can help to describe other options to achieve the same desired effect.

I'm hoping that in your description of "focus lock", you're not inadvertently describing AE lock(auto exposure lock! This is where a breakdown in communication may have occurred.

Reason is because locking focus .. or more accurately securing focus to a specific plane, is usually best done either manually, or with the AF-On button method.
Exposure lock is a totally different beast and has nothing to do with the original question posted.

If you've ever tried the AF-On method for focusing you'll understand why it's an important feature on a pro/semi pro body. It's akin to having full time manual focus control but the advantage of the camera doing the focusing for you.


Anyhow, I'm not trying to persuade you to do anything .. just trying to describe to you, an option for operating your camera for the situation you had trouble with.

[Epoc]

I always thought that you should turn off the IS (which is actually OS on a Sigma) for moving shots with higher shutter speeds which I presume you will have doing surf shots.

[Warbler]

Okay, stupid question time. Are you using AI-Servo or AI-Focus, or are you using single shot? I don't have either a 5DMkII or a Sigma 150-500, but I do have a 5D, a 5DMkIII and a couple off Sigma teles. I've found best results from the Sigmas is use a monopod, set the camera in either AI-Servo or AI-Focus and use a single focus point. If using burst, I usually encounter the odd OOF shot within a series. That even happens on my 1-series bodies with the Sigmas. I've also found that using the AF-On button as suggested by people above, is easier to do with the camera/lens combo's weight supported by a mono. OS is not going to be of any benefit to you in shooting a moving subject if you are already getting 1/1000th of a second as you mentioned. OS will only help you with slow shutter and camera shake. Also, the focus is improved greatly if you can fill the frame with your desired subject. The 5D Mark II was not designed as a sports weapon, but some sports it can handle quite well. I would have thought surfing would be one that it does okay. Only one person in the shot at a time.

[Fruengalli]

Okay, stupid question time. Are you using AI-Servo or AI-Focus, or are you using single shot? I don't have either a 5DMkII or a Sigma 150-500, but I do have a 5D, a 5DMkIII and a couple off Sigma teles. I've found best results from the Sigmas is use a monopod, set the camera in either AI-Servo or AI-Focus and use a single focus point. If using burst, I usually encounter the odd OOF shot within a series. That even happens on my 1-series bodies with the Sigmas. I've also found that using the AF-On button as suggested by people above, is easier to do with the camera/lens combo's weight supported by a mono. OS is not going to be of any benefit to you in shooting a moving subject if you are already getting 1/1000th of a second as you mentioned. OS will only help you with slow shutter and camera shake. Also, the focus is improved greatly if you can fill the frame with your desired subject. The 5D Mark II was not designed as a sports weapon, but some sports it can handle quite well. I would have thought surfing would be one that it does okay. Only one person in the shot at a time.

Thanks Warbler,
I do use a monopod & as I mentioned I was using servo with centre point focus but not half pressing the shutter button & actuating constant focus & tracking before I fired. My bad operation technique.When I went back to one shot which is my normal use I got far better results. Ian(above) mentioned not to use os for moving subjects so one more bit of testing to do.Thanks for the input.

- - - Updated - - -

I always thought that you should turn off the IS (which is actually OS on a Sigma) for moving shots with higher shutter speeds which I presume you will have doing surf shots.

Thanks Ian I had not heard this so I will have to do some more testing.
Thanks for the info

[Tannin]

Interesting thread. Three thoughts cross my mind.

1: Sigma's OS might not like the monopod. Early generation IS/VR lenses from Canon and Nikon hated tripods. Later models with second and subsequent generation IS/VR auto sense and adapt themselves to hand-held or tripod.

2: The general rule with moving subjects that don't move too fast is keep the IS on. (I've never done surfing, but I would certainly use IS if I did.)

3: The AF system on the 5D II is seriously primitive - the worst AF of any recently produced camera I know of. I only ever use mine for landscapes, and even for that it is poor. So you have to work with the damn thing and force it to do what you want! But you are a 5D II owner, you know this.

[Fruengalli]

Interesting thread. Three thoughts cross my mind.

1: Sigma's OS might not like the monopod. Early generation IS/VR lenses from Canon and Nikon hated tripods. Later models with second and subsequent generation IS/VR auto sense and adapt themselves to hand-held or tripod.

2: The general rule with moving subjects that don't move too fast is keep the IS on. (I've never done surfing, but I would certainly use IS if I did.)

3: The AF system on the 5D II is seriously primitive - the worst AF of any recently produced camera I know of. I only ever use mine for landscapes, and even for that it is poor. So you have to work with the damn thing and force it to do what you want! But you are a 5D II owner, you know this.

#1 Its only about 6 months old so I'm pretty sure its OK with the mono.#2 I'm pretty sure a lot of my grief is op error. Got a couple of sharper shots the other day. #3 I only use centre point focus (old habits die hard) & have to say, prior to this lens, for a primitive system it very rarely misses unless I screw up. I know its not an "L" but I reckon I can get some shots out of it.

[Epoc]

Here's a post of some surf pics I did a few months ago with the big Siggy. All were shot without OS. Shutter speeds were high enough to negate its need.

http://www.ausphotography.net.au/for...780-Surf-shots

[Tannin]

Cheers Fruengalli. I think you are spot on in your assessment that mostly you just need to keep working at your technique with the new lens. New gear always takes a while, and long lenses take a long while to become familiar with. Stick to your knitting!

As a matter of detail, I wasn't referring to the age of the lens so much as the sophistication of the IS system design. Sigma have not been doing IS for very long and may not have got around to the finer points of it. Alternatively, they may have looked at the existing products carefully and been able to design something similar from scratch without having to repeat prior mistakes. Do Sigma OS lenses auto-sense tripods? I'd guess that they do but I have no hard information either way. Is there a way we can find out? Is the Sigma OS system documented in detail anywhere?

As for focus, I was talking about the camera, not the lens. (More on this in a moment.) I was about to add "there is nothing wrong with the AF in a Sigma lens 'cause there isn't any AF in that (or any other) lens" when I was reminded to mention that it is an f/6.3 lens, and as such is theoretically unable to AF on any non-pro body. Note that I said theoretically! In practice (as you have seen for yourself) the camera can still AF at f/6.3, but we should remember that it is operating outside its design intention. It was designed to AF at f/5.6 or better, and aperture really does make a difference to SLR-style phase detection AF - not just a difference of degree but a difference of kind. So you can expect it to be a bit slow and vague by comparison to (e.g.) a 400/5.6. I have only used the big Sigmas casually (swap gear with a mate for ten minutes, that sort of thing) but that casual use and the good results of people using the big Siggies makes it pretty clear that they are perfectly capable and, used with care, can give great results.

Back to the camera. Centre-point focus seems to be the least-worst aspect of the 5D II's otherwise primitive focus system. And all technical matters aside, using centre-point only is (I think) often a good idea because it keeps things very simple and leaves you free to concentrate on getting other stuff right. I often find myself messing about selecting focus points on the 5D II and the 50D where I really should be just using the centre point intelligently and worring about important things. (Much less so on the pro bodies where you have a vastly better range of focus points and there is nearly always one in the spot you need it, so you just go there without any fuss or fiddling.) Don't get me wrong: I love my 5D II and it makes awesomely good pictures. I just wish it had a 1D III focus and exposure system. One day I'll get a 5D III instead. But the 5D II will do the job in the meantime.