Wildlife photography often involves cropping an image, because you can't always get closer to the subject. This great video explains why you might want to consider your ISO setting a bit more when you know you're going to crop your image.
In this video from Steve Perry, he points out that most people don't take into account ISO when they shoot an image that they know they are going to crop. I'm very mindful of my ISO setting when I'm shooting. However, this video has highlighted an important aspect that I hadn't previously considered, making me one of those people.
Steve uses example images to show the differences between image details at various ISO settings. Something everyone should do is shoot test photos and compare them on their computer. Exploring what works and what doesn't is one way that you can not only learn your camera and gear but learn its limits as well. You'll also want to do this with your various lenses as well.
The more you know what your camera and gear can and can't do, the better you'll be at capturing that image just the way you want. Check out the video above for all the good points that Steve makes.
I mean this is pretty much why APS-C cameras are about a stop noisier than full frame and micro 4/3 about another stop...
Who isn’t shooting at the lowest possible ISO all the time?
Actually, since I've bought a new camera (which doesn't output an unuseful image with a little bit higher ISO), sometimes I like shooting at ISO 400 or even 800 when I want to combine a handheld shot with a high f-stop and a quick shutter-speed.
But you're still using the lowest ISO to accomplish your objective is the point I'm making. You're not shooting at ISO 1600 when 800 or 400 are enough.
Nobody is cranking the ISO just for the heck of it is what I'm saying. Whatever ISO is required to get the job done will produce whatever noise it produces. If someone could go with a lower ISO, they already would, whether they planned to crop or not.
I shoot real estate on a tripod. I could shoot as low as ISO 100, but I choose 320 all the time to speed up the process. This is pretty common amongst other RE photographers.
First, thank you F/stoppers for posting my video - greatly appreciated :)
As for always shooting the lowest ISO...
It depends on the subject. For wildlife photographers (and many others I'm sure), we're often faced with a range of options, not just a single perfect shutter speed, ISO, and F/stop. Here are just a few scenarios that came to mind:
For example, when I'm shooting macaws in flight in Costa Rica, I find that 1/3200th of a second is about the sweet spot - I very seldom have an image ruined by motion blur at that speed. However, if 1/3200th puts me at say ISO 6400 and I know there may be some cropping afterward, I'll (begrudgingly) drop to 1/1600th and knock my ISO down to 3200. My keeper rate won't be as high since more images will be ruined by motion blur, but they photo won't be a complete loss because of noise overwhelming the detail either. Basically, I'm trading a higher keeper rate for the lower ISO.
Another scenario that comes to mind is hand-holding. Maybe you can hand-hold your given lens at 1/1000th (thinking telephotos here), but that puts you at ISO 6400 on an image you'll know you need to crop. So, you grab a monopod or even a tripod so you can knock your shutter speed down to 1/500th or even 1/250th. In this case, you trade the flexibility of hand-holding for the lower ISO.
It can also happen with F/stop. Many BIF photographers will drop their lens down a stop to a stop and a half from wide open in order to gain a little extra DoF and keep the entire bird in focus (and have a little fudge factor for slight misses in focus). However, if the light is dim, you may be willing to trade that extra DoF for a lower ISO.
Finally, I think it's good to just put it in people's heads :) In conducting my workshops, I often find people are so excited about what they are shooting they forget to double-check that they are using the best shutter speed and F/stop - often shooting a far faster shutter speed than they need. If this video reminds them to look at their ISO when they know they need to crop, I'm sure a lot of people will find that useful.
I'm a Canon user, but another option would be to switch to Nikon or Sony and keep the higher ISO. I find Nikon's D850 12,800 pretty close to my 5DS 6400, and their 6400 pretty close to my 3200.
One other option is to shoot with more resolution than you need. When I downrez my 51 MP shots to 24 MP, the resultant shot cleans up pretty well. 24 MP is completely sufficient for, say, a magazine spread.