Trogon Photo Tours

March 2015 - This article discusses iso selection for bird photography
 
The biggest impetus for me changing from shooting slide film to digital about 10 years ago was that I saw that photographers were routinely shooting at iso 400 when shooting digital while with film photography I was shooting at film speeds of 100 or 200 and at 200 the images were quite grainy.  I realized that for action photography and getting a faster shutter speed, digital would be the way to go.  So how did I determine which iso I would use when I started shooting digital?

The lower the iso that you use generally the less noise you will have. more dynamic range captured and the higher quality image you will get.  However the higher iso that you use means that you will be able to use a faster shutter speed and/or more depth of field to get your image. Shutter speed is critical for stopping the action and helpful for sharpness especially when shooting handheld.  Capturing multiple subjects often means using a wide depth of field.  Understanding this trade off between image quality (lack of noise) and ability to stop the action and use more depth of field is paramount in deciding which iso you will use.

Which iso you choose will depend on 1) Which camera you are using? 2)  What you are trying for in the photograph? 3) How will you use the photograph? 4) What are your lighting conditions for the shot? 5) How much do you think you will crop the shot?

Least Grebe photographed at Estero Llano Grande State Park, TX March 2015.  Canon 7DII 500F4 1/1000 at F5.6, iso 800, handheld.  The next 2 images will illustrate why I used iso 800 which with the new 7DII gives you reasonable results but not great in terms of image quality and noise.  Photographing this at iso 400 to 500 would have given me a better image quality but not a fast enough shutter speed to stop the action.  I am steady enough handholding that I could have made a sharp image even with the lower shutter speed if the bird wasn't moving quickly as was the case here.  The thing about bird photography is you never know when the action is going to happen (bird takes off, flaps it's wings etc) so you need to be prepared for it before it happens.  We visited Estero Lllano Grande for a few hours during our recent March Texas photo workshop and found it very productive so we are adding more time there during all of our future South Texas workshops.  

Least Grebe photographed at Estero Llano Grande State Park, TX March 2015.  Canon 7DII 500F4 1/1000 at F5.6, iso 800, Av mode 0 EV, handheld.  Besides just sitting on the water the grebe would occasionally shake itself or quickly run across the water.  This is the reason I was at iso 800 rather than at 400 or 500, I needed to have enough shutter speed to stop the action and I was 1 stop down from wide open to get sufficient depth of field to get most if not all of the body sharp.  In this case the body isn't very sharp because of the motion of shaking but the head is nice and sharp.  At a lower shutter speed and iso it might not have been.  I didn't manage to capture it running across the water as it happened so fast but I imagine I may not have had a fast enough shutter speed to get that sharp.  The reason I didn't go to iso 1600 to get that fast of a shutter speed is that with this camera body I felt the image quality would suffer too much.  That and it was unlikely I was going to get the shot anyway.  After shooting with the 7DII for a while I changed to my 5DIII which performs better at higher isos in an attempt to get that shot and photographed at iso 1600 for a period of time.

This gets one of the most important issues when selecting your iso - what was I looking for in the shot?  With the grebe just sitting or swimming on the water and enough lighting available I certainly could have been shooting this at iso 400.  That would have meant that my image of the grebe sitting on the water would have no or very little noise and if I wanted to I would be able to print it quite large without using noise reduction.   However an image of a grebe just sitting on the water while nice because I haven't photographed this species closely before is not a particularly compelling image and certainly not one that I'm going to end up printing large.  Most of my images I use for web presentation or send to my stock photography agents.  I rarely print them large and put them on my wall.  I am more interested in capturing compelling action and behavior shots of birds, not static ones.  Therefore I was set up with an iso here that allowed me to have a shutter speed that was fast enough to at least partially stop the action if it occured.  Well, sure enough the grebe shook a few times and took off running across the water a couple of times. The camera I was using, the 7DII shows a little noise but not a lot at iso 800 so I am still getting pretty good image quality.  At iso 400 and that F-stop I would have had a shutter speed of about 1/500 which wouldn't have been fast enough to stop the action. 

Harris's Hawk photographed March 2015, Santa Clara Ranch, TX.  Canon 5DIII 500F4 1/1250 F5, iso 1250, Gitzo tripod, Wimberley head.  In terms of flight photography with large birds I would ideally like to have about 1/1600 or more and 1 stop down from wide open or more to get the whole bird in focus.  However when I took this image at Santa Clara Ranch recently we were down to almost last light when the hawk started coming into the feeding station.  To get this flight shot at those settings I would have had to be at iso 2000 which would be pretty mediocre even on the 5DIII. So I went just below each of those settings knowing that I can usually stop a large bird at 1/1000 or more and just using a touch less depth of field got me down to an iso that this camera has quite a bit better results at.  Note that I was using my 5DIII here, not my 7DII largely because it has better iso performance in low light. Due to the fading light conditions and the fact that I wanted to get a flight shot, I used a higher iso than my default (usual) iso for that camera.  An excellent website for getting an objective opinion of iso  performance is www.dxomark.com . To get access to their camera sensor ratings click the link here.  Find your camera, click on it and check the scores for sports (low light performance)  For example it lists the Canon 7DII with an iso test performance score of 1082.  This means that the 7DII should have reasonably good performance up to iso 1000.  For the 5DIII it lists a score of 2293 which would mean reasonably good performance of up to iso 2000.  The Nikon D810 has a score of 2853 and the Nikon D7100 has a score of 1256.    What I have found in practice is that if you halve the www.dxomark.com score you will generally have very good performance.  So that means with the Canon 7DII my default iso would be 500.  For the Canon 5DIII my default iso would be 1000 but in practice I use 800 partially because I know that with a full frame camera I will be cropping more than I would be with a crop sensor camera and partially because at iso 800 I am usually already getting a pretty fast shutter speed.   In general full frame cameras will perform much better at higher isos than cropped sensor cameras.  All of this gets to what camera are you using?  With different cameras you will use different isos. 

White Ibis - photographed March 2015 from the Jack Flash photography boat off of Rockport, TX.  Canon 7DII 500F4 1/2500 F5.6, iso 400, Av mode with -0.3 evaluative metering, handheld.  This bird feeding on a crab was quite far away and I knew I was going to have to crop the image a fair bit, this is about 25% of the original. So I used a lower iso than my default for this camera as there was also plenty of light to work with.  Cropping reduces image quality and increases noise so if you are going to have to crop a lot it makes sense to use a lower iso than normal if lighting conditions allow for it.  

Common Pauraque photographed March 2015, Estero Llano State Park, TX.  Canon 7DII 500F4 1/200 F8, manual exposure, iso 1600, pop up flash at -0.3, handheld.  This was a situation where I ended up using a higher than ideal iso for the camera that I was using as a result of a few issues.  I like to shoot handheld and it was a rainy, windy day.  I was aware that we would probably find one of this species as it's a great location for Paraque and that it would be fairly dark where they were roosting.  But it was so cold (low 40's but windchill in the 20's - very unusual for South Texas) that I didn't want to carry my tripod so I figured if we found them I would make the best of it.  This bird was very cooperative sleeping and roosting and allowed us to take many images of it.  I tried the 5DIII which does better at this iso but I felt I also needed to mix flash in.  The problem was I also left my flash in the vehicle and didn't want to walk back and get both the tripod and the flash.  The 5DIII doesn't have a pop up flash, while the 7DII does.  So I took some images with the 7DII and the pop up flash.  The bird was quite close so I needed F8 to get both the face and beak in good focus, handholding at 1/100 the images weren't sharp so I went to 1/200 and iso 1600.  I typically wouldn't want to photograph with this body over iso 1000.   With a bit of noise reduction in ACR this turned out very nicely I think, it was helpful that I was close to the bird and didn't have to crop it at all.  Estero Llano Grande is generally a reliable location for this species. 

There are some photographers who use auto iso to select their iso and I sometimes am asked why I don't.  The reason is that if there is available light I'm going to use it to be prepared for action photography all the time, so I don't want to limit my shutter speed to say 1/500 or another number.  In one situation I'm going to want to use a shutter speed of 1/2000 while in another situation I am going to want to use 1/200.  For example I could be photographing in an open area where I could get flight shots etc one moment and then find a Paraque roosting in the shade the next moment.  If I was using auto iso I would have to change the settings anyway to get the shutter speed and iso I wanted so I just prefer to change the iso manually.  If I did use auto iso I would set the lower limit of the iso at iso 400 not iso 200 or 100 like I sometimes see photographers use in conjunction with something like 1/500 of a second.    On most digital cameras now there is little or no noise at iso 400 and you are just losing speed that you could use to capture action photography if action does occur.  Another method of using auto iso that I have heard is that you set your auto iso to a moderate speed - something like 1/500 to 1/1000 and then you have the custom functions set on your camera so that with one click of the button you change to action photography.  The settings are then at whatever you have set that custom function to specifically for action photography, something like auto iso with a 1/2000 shutter speed.  The reason I don't do that is that with birds in the time it takes to push that button you will have often missed the action opportunity because the action happens that fast because birds can fly.  I could see where if you were working with mammals that approach would make more sense. 

Plate-billed Mountain Toucan photographed December 2013 near Bellavista Lodge, Ecuador.  Canon 5DIII 500F4 1.4x 1/160 at F8, iso 1600, Gitzo tripod, Wimberley head.  When I am photographing in forests I typically don't worry about trying to get action bird photographs and just set up with whatever iso I think I will get good results with while still having sufficient shutter speed to get a good static image.  That was the case here when we first photographed this toucan nest.  The 5DIII gives reasonably good results at iso 1600 if you don't have to crop too much (this is about 50% of the original).  I didn't want to go down to iso 800 because with that focal length and the bird moving a bit as it was feeding it's babies the shutter speed would have been too low. 

Plate-billed Mountain Toucan photographed December 2013 near Bellavista Lodge, Ecuador.  Canon 5DIII 500F4 1/2500 F5, iso 3200, Gitzo tripod, Wimberley head.  After we had gotten photographs of the toucan feeding at the nest and poking it's head out we decided to go for flight shots.  So at this point I increased my iso, took off my teleconverter and changed my F-stop to pick up more speed.  When I am photographing in the forest I only change my iso to an action type of speed if I am focusing on action shots, while if I am photographing birds out in the open such as at Santa Clara Ranch I will almost always keep my iso and speed at an appropriate level for stopping the action.  

In conclusion when deciding what iso to use for bird photography think about what you will use the photo for, what camera you are using, what you are trying to capture, what kind of shutter speed are you getting with the lighting conditions and how much you think you will crop the shot.

For me I find the majority of the time I am photographing in what I would consider middle range isos - 400 to 800 on the Canon 7DII and 500 to 1600 on the 5DIII.  To go to lower iso's there isn't much point because you are already getting very good image quality at 400-800 and you are losing speed in dropping it below those numbers and gaining very little in image quality.  There are exceptions of course, such as artistic blur photography where you are trying to show motion.  Happy shooting to everyone.