Beginner Quick beginner question on capturing moving objects (when AF-C doesn't work)

[RichW9]

Hi again, I hope it's okay to ask another question here. I'm lucky enough to live in the coast (Aberdeen) and in my 1 hour coronavirus exercise time I cycled along the coast and spotted some dolphins. They were moving really fast and I couldn't get the cameras AF-C thing to track them because they blended into the sea and were so far away. I was using a shutter speed of 1/100 which I now realise I should have set to 1/200 or maybe higher(?). Does anyone have any advice that I could follow next time I see them? Thanks in advance.

Below are a couple of the best images I got, I used lightroom to try sharpen them a bit::

 

[Teflon-Mike]

Remember what we were saying about f-No being a ratio of aperture diameter to the lens focal length? I expect that because them porpoise were so far away, you were using that Tammy super-zoom, and zooming a long way in. hence restricting your f-no. Tip... use less zoom! (or cheat a bit and do it in post cropping harder!)

Next. If the flippers were 'so' far away, and they wouldn't need to be all 'that' far off, then the auto-focus should make little odds, they are beyond the hyper-focal distance where anything will be in acceptable focus, anyway.

Your camera was probably struggling to find focus, because there wasn't much contrast between the subject and the back-ground... back-sea?- they were in, to actually get a bead on, at any speed, whether they were moving very fast or not! An instance where your electronic 'easement' is probably less than helpful, and you'd have had more success switching the AF off altogether, and focusing manually at hyper-focal distance, where anything close or beyond that will effectively be 'in' focus regardless.

Back to the settings; this doesn't look like a particularly low light situation, so you should have been able to something close to f16-Sunny, so you could have got the dolphins in focus and not motion blurred using a faster shutter speed.. And higher f-no's, to maximise depth of focus and Focus tolerance, whether imposed by using a lot of zoom or not, shouldn't be an inherent hassle.

You mentioned 1/200th, so again, I suspect you were using a lot of zoom.... hand holding a 200mm lens, that is about as low as you would probably want to go to avoid hand-hold camera shake.... and stopped down on aperture, to increase your Depth of Focus, you would have had to have and upped the ISO to balance the exposure.

And in prior post, I recall you mentioning being averse to higher ISO settings due to worries over 'noise'. Don't be! Noise is like sharpness a much hyped idea, and its not so dependent on the ISO setting as the contrast in the scene, where if there isn't much then the electrickery will struggle to work out which pixels should be brighter or darker than others.

But main niggle here is that the Dolphins are sea coloured. so there's not a lot of contrast between them and the sea, and you will struggle to get a 'sharp' image because that is as much about the contrast and perceiving the subject in the picture, as it is about either focus or noise and such... as prior posting, stop fretting about this mythical 'Sharpness'... worry about whether the picture is pleasing.

Use more ISO, up your shutter speeds with that long lens, and don't be so greedy to fill frame with subject using so much zoom.... and remember you can crop after the event, you have plenty of pixels to play with; and if that isn't enough? Well, you cant win them all, and the best photo's don't just occur when we happen along by chance, they are made by planning, and choosing the best time and location and light to get what you hope to achieve knowing where the niggles lie. Again, is the photo pleasing or not? Dont over-estimate the merit of the technical.

 

[Scots_quine]

And use single point focus.

 

[AndrewFlannigan]

Mike and Joan's suggestions are good. My own approach in a case like this is...

• switch off the AF
• set the lens to infinity
• switch to continuous shooting mode

...and concentrate on moving the lens as smoothly as possible while tracking the dolphins.

 

[andrewc]

Looks a nice day so you could have safely raised the shutter speed significantly. For example, sports where you want to freeze the action, you'd possibly aim for 1/1000th second. I'd use single point focus, a faster shutter speed. I'd probably use single shot shutter more but fire of multiple shots.

A faster shutter speed reduces the problems of camera shake, but you can have problems with heat haze and other atmospheric effects, plus the limitations of the lens.

As some newcomers to dSLRs use Liveview as their default as thats what they are used to doing with compacts and phones, I would suggest using the viewfinder as you will hold the camera much more steadily than at arms length to see the screen.

 

[Teflon-Mike]

As some newcomers to dSLRs use Liveview as their default as that's what they are used to doing with compacts and phones, I would suggest using the viewfinder as you will hold the camera much more steadily than at arms length to see the screen.

I'd forgotten about this, and concur.

Remember comment in prior post, I did a shutter-speed 'limbo' with my daughter when she started her GCSE photo, and was progressing from compact and camera-phone, and not used to using the peep-hole view-finder. Claims for the VR on our lenses were that you could hand hold up to three stops slower than without,,,, utter nonsense, AFAICT. Remember that the rule of thumb is to keep the shutter above 1/ lens (longest) length. The lens doesn't get any better balanced at less zoom, its just that the subjects smaller in the frame, so any movement is less magnified. Its like holding a broom by the tip compared to a match-stick, leverage.

But anyway, I was shooting at 35mm, hand held down to around 1/8th seconds, and still getting acceptably sharp images. Daughter, after a little practice was down to around 1/10th, and after a bit more, was shooting a 135 'prime' on an adaptor, hand held, down as low as 1/30th and getting images sharp enough for course submission.

There REALLY is no substitute for good hand holding technique.

First get off the back-screen, use the optical view finder's peep hole. I mean, you paid umpety hundred for a Digital Single Lens Reflex camera that has a reflex mechanism in it, to peer over the top of the sensor, if you aren't going to make use of it, you have wasted a heck of a lot of your money, and the cameras capability, before you even begin. Don't hold the camera at arms length.

Use two hands and cradle body and lens.

Tuck elbows in to body and make a bridge to 'brace' the camera

And breath 'easy'.. and like a sharp-shooter, wait until you are at a breathing 'space' to press the shutter.

And again like the sniper, SQUEEZE the shutter, rather than tugg the trigger.

Its all pretty simple stuff... but 'key to better photos.

 

[RichW9]

Thanks @Teflon-Mike and others, some very clear points there, will work through them and hopefully next time be more prepared!