Hitting Focus in Low Light

Hi folks,

I am after some advice about the best way to nail focus in low-light situations (stemming from another thread that I was on and didn’t want to take OT!).

I’ve been spending a lot of time over at local zoo’s and wildlife parks, and I am particularly enjoying the reptile areas. I’ve had some success in the past with decent shots, but my most recent visit ended up with disappointment and a vast majority of out of focus pictures. The problem I had is that the pictures looked fine on the viewscreen after taking them and I thought I’d nailed it. It was only when I got home and put them onto the PC that I realised that most of them were garbage. I am sure there must be some specific technique or camera setting that I am missing, but I have been trawling other posts, photography guides, my camera manual etc etc and I can’t quite pinpoint where it went wrong. One of the suggestions from the other thread that I am on was that I need to be using a relatively fast shutter-speed to maintain focus, and looking at most of my pictures they varied about 1/4 , 1/6, 1/10 etc … so definitely slow! But this was in a low-light environment where flashes aren’t allowed and I was already pushing the “noise-limit” with 1600 ISO.

Here are some examples of what I got. These looked great on the viewscreen, but as you can see, once you get them onto the PC you can see the focus is totally off (it's obviously much more noticeable on the full sized images):

I'd say shutter speed is your problem here. Far too slow for that kind of focal length and hand held.

Better to get a bit of grain in the shot and it be sharp than a blurred shot. Is there any way you could take a tripod with you. You could pull that off if it was on a tripod or monopod

Are you using a tripod? Shutter speeds that slow with a lens and camera that size are going to be very difficult to pull without some camera shake. You can try a monopod for easier walking around the zoo as well, or finding something to lean on to support your arms or camera. A faster lens can help but at 300mm finding a lens that allows a larger aperture is going to cost you big bucks.

You can try turning it to TV mode and taking off auto ISO- then experiment with higher shutter speeds and ISO higher than 1600. Auto ISO can be set in your camera menu to a limit- try taking similar shots at 3200 or 6400 ISO to allow you to increase your shutter speed and see if you are happy with the results.

Orias wrote in post #16601573
Hi folks,

I am after some advice about the best way to nail focus in low-light situations (stemming from another thread that I was on and didn’t want to take OT!).

I’ve been spending a lot of time over at local zoo’s and wildlife parks, and I am particularly enjoying the reptile areas. I’ve had some success in the past with decent shots, but my most recent visit ended up with disappointment and a vast majority of out of focus pictures. The problem I had is that the pictures looked fine on the viewscreen after taking them and I thought I’d nailed it. It was only when I got home and put them onto the PC that I realised that most of them were garbage. I am sure there must be some specific technique or camera setting that I am missing, but I have been trawling other posts, photography guides, my camera manual etc etc and I can’t quite pinpoint where it went wrong. One of the suggestions from the other thread that I am on was that I need to be using a relatively fast shutter-speed to maintain focus, and looking at most of my pictures they varied about 1/4 , 1/6, 1/10 etc … so definitely slow! But this was in a low-light environment where flashes aren’t allowed and I was already pushing the “noise-limit” with 1600 ISO.

Here are some examples of what I got. These looked great on the viewscreen, but as you can see, once you get them onto the PC you can see the focus is totally off (it's obviously much more noticeable on the full sized images):

The setup I was using for the day was as follows (from what I can remember):

Canon 500D
Sigma 70-300 DG Macro F5.6
Camera in AV mode set to F5.6
ISO Auto
Spot-Focus (using middle-marker to focus on subject’s eyes)
Servo AI focus
Centre Weighted metering mode

A lot of the shots were taken at full 300mm zoom with the “Macro” switch turned on (without it the focus wouldn’t “reach” far enough to find the subject).

So is there some technique I am missing, or some “eureka” setting that will solve my issue. If I really do need a faster shutter speed, then how can I do this without pushing the ISO crazy-high and getting noisy images. Is it a limitation of my Lens or Camera itself that needs to be changed?

Any advice would be great .. I'm planning more trips
Cheers, Ori

Most likely, those images have no focus problems. The issues, clearly demonstrated by the images' EXIF data, are slow shutter speeds - 1/15 and 1/6. You're dealing with motion blur, not misfocus. The easiest solution is to get a quicker shutter speed with a higher ISO. Run the camera at ISO 6400 if necessary and clean up the resulting noise with a free noise reduction program such as the Noiseware Community Edition Standalone v.2.6.

If you've ever read a message on this forum stating that noise is better than motion blur, you're clearly in that circumstance.

The first thing that occurs to me is that f/5.6 is on the open side, reducing the depth of field somewhat. I remember doing a Macro session at our local camera shop and the expert got us all to use f/16 simply to increase DoF.

Then why not increase the light level? If this is in the wild then that might be a problem, but if this is simply a studio macro then light levels should not be an issue.

Lastly, have you tried manual focus?

edited to add: Like a comment already made, I am assuming you are using a tripod?

Sorry, I did forget to add that I was using a tripod, yes. However, my remote shutter release was broken (which I didn't realise until I got there), so some of these focus issues may well be the result of me pushing the button. I could have used a delay, but with moving subjects it's always a but of a gamble. It was also relatively busy with lots of screaming kids and buggies all over the place, so I didn't have the time I would have liked to set the shots up properly as I was very conscious of being "that guy" that's always in the way. The other issue in this environment was the humidity, and fogging on the lens.

Unfortunately I have no control at all over the lighting in these circumstances, so flash and/or additional lighting are no option

I think I could probably use a bit more DOF too, but that's just going to compound the problem I assume. I didn't try Manual Focus on this particular session, but I have tried it in the past and I don't 100% trust my eyes! I'll try to make my next visit during the week when it's nice and empty I think!

Thanks very much for the suggestions so far. I may well experiment with that noise removal software when I get home. Although I am not sure if my 500D has the ability to set an Auto-ISO limit (I know other models do).

Cheers, Ori

You don't have to use auto, just wack it up to 6400 and see what it's like. Saying that, this will only get you 2 stops more light 1600->3200->6400 so that's still not going to get you anywhere near a fast shutter speed. Saying that, you are on a tripod you maybe it'll give you what you need. Give it a go, you might be pleasantly surprised

Nice .. I'll give it a go and see what happens. Could Image Stabilisation have anything to do with any of this? I always have it turned on, but I am not sure if there is any reason that IS would (or would not) make things better or worse. The name suggests it must be helping

You should have IS off when you're on your tripod. Also, i'd say get your remote shutter working again as this will be key to getting a still shot

Okay, I'll give that a shot too. I didn't realise that there was a downside to using IS if it wasn't strictly necessary. I think I just figured that any extra stability was a good thing!

Thanks again for all the advice!
Cheers, Ori

chimpsinties wrote in post #16601706
You should have IS off when you're on your tripod. Also, i'd say get your remote shutter working again as this will be key to getting a still shot

This is only an issue with earlier lenses. So.. depends on what lens you have and whether it even applies to your Sigma or just Canon lenses.

From this canon website

Using IS with a tripod

When using certain early models of IS lenses with a tripod it was necessary to turn off the IS function. This is because of a phenomenon known as ‘Shake Return’. Shake Return occurs when the IS system tries to correct vibrations to which the system itself contributes. When the IS lens sits on a tripod, the IS detection gyros pick up any tiny vibrations or movement; these might be caused by the tripod being knocked, or the photographer adjusting a camera setting.

The IS system then swings into action to correct that movement. The movement of the IS lens group causes its own minute vibration, which is in turn detected by the movement sensor, which triggers another correction. This ‘feedback loop’ can continue endlessly, resulting in the addition of unwanted blur to images that would be sharper if the IS function was switched off.

So I just had a quick test at home and it seems that I'm not really going get much faster shutter speeds without either a very good (expensive) lens, or some additional light source (which isn't an option).

But I turned on the additional ISO levels to get access to 6400 & 12800 and had a go. I can still only get to about 1/30 shutter speed (although I am testing at the darker end of the light that's available). But actually just using the presets on the software that DC Fan suggested (Noiseware Community Edition) came out with much better results than I expected. Obviously I don't really want to be going that high, but it's nice to know that it's not the end of the world if I need to ... here are the before and after test shots I did for context ...

Original shot @ 6400 ISO:

And thanks very much WaltA, that's quite interesting information! Actually, the Sigma lens doesn't have the IS, but the Canon 17-55mm (bundled) lens does, and I never turn that off. I sometimes use that for the reptile shots when I have the option to get up close, so I'll certainly take this into account next time!!

Thanks again,
Cheers, Ori

WaltA wrote in post #16602375
From this canon website

Using IS with a tripod

Holly c**p, I only just decided to actually read that. IME a load of marketing BS, but I guess it is on Canon's website so it must be true

They even go as far as to essentially say the IS on the 24-105 does not need to be turned off. Man, how many times have I bracketed 3 shots on a tripod only to find out they are not exactly aligned becasue the IS moved between shots - a lot more than I care to remember. Even the new 100L messed up a focus stack (or 5) becasue I accidentally left the IS on.

I think if you had a lens that could do even f2.8, you would be pleasantly surprised at the lower ISOs you could use. The "bundled" lens is the 18-55 and it is a 3.5-5.6 lens. The 50 1.8 would really let you get back down into low ISOs for an expensive price

Why using AI servo shooting lizards? Seems like one shot AF would be preferable.