Working with D4 and EOS 1DX – Autofocus in very low light

Test of the Canon EOS 1DX autofocus in low light

Canon EOS 1DX with 70-300mm 4-5,6L at 300mm
1/8 sec at f/5,6 ISO 12800

Yesterday evening we had a bad storm with wind speeds as high as 108 Knots! This morning everything was quiet again and I went on a short trip on my skies. In my backpack I had the EOS 1DX and I was looking forward to see how the autofocus performed in low light. I work a lot in low light and even more after the possibility of good image quality with high ISO. The early mornings and late evenings are often the time where the mammals are active and to be able to work in these circumstances are very important to me. Have a look at my photo project The Land Without Sun

I have been using the D4 autofocus a lot in low light and almost complete darkness and I am really amazed about how it can achieve focus in these conditions. When I look at a subject I have a pretty good idea if it is too dark for the autofocus or not and my guide line is that if I can see the subject just a little in the viewfinder, the D4 will get it too.

EOS 1DX One Shot AF much better than AI Servo in low light

Today I photographed two arctic hares and some fox tracks in the snow with the moon as the only light. For some of the photos I got a little help from the light from the Thule Air Base. I tested the autofocus in several situations, and my conclusion at this time is that the One Shot autofocus on the EOS 1DX is the only useful one in very low light. The AI-Servo AF is worth nothing for me when I do my low light photography. It simply continues to go from the near limit to the infinity and back again without locking on the subjects.

Test of the Canon EOS 1DX autofocus in low light

Canon EOS 1DX with 70-300mm 4-5,6L at 180mm
1/20 sec at f/5 ISO 5000

The One Shot AF is better, but it becomes incredible slow when I push it to its limit. When it misses the subject it takes about 10 seconds to go from 15 meters to the near limit and back infinity. Very often it fails to se the subject. Thanks to the bright and nice viewfinder, I was able to focus manual in most of the cases when the One Shot AF failed.

This means that when I am in a situation where the light is too low and I can’t see the subject clear enough to make a manual focus, the AF in the Canon EOS 1DX will not be able to help. This may sound a little theoretical but it is not. The picture of the Arctic hare is made with manual focus and in situations like this I really love to rely on the autofocus so I can concentrate on the subject and the composition.

I decided to push both autofocus systems to their limits

When I do my small tests I really want to make sure that I make the right conclusions – for my own sake. So I skied back to my room to get the D4 so I could make a fair comparison. I decided to push both autofocus systems to their limits and my definition of “the limit” is a situation where the autofocus sometimes manage to find the subject and sometimes not – about 50/50. The final photo has to be in focus. Well you are right – I do have too much time in this dark season in Greenland;) 

For the Canon EOS 1DX I used the One Shot mode (the best for low light) and for the Nikon I used the C mode (AI Servo) because it is as good as the S (One Shot). The limit of the Canon was a situation with 1/20 sek f/5,6 ISO 12800 on 300mm. It was never close to focus with the AI servo and this was the limit of the One Shot mode. The same subject and the same settings on the Nikon – The AF nailed the subject every time without any problems.

So just to se how close I was to the limit of the D4 I found a darker place with the same kind of subject and after this an even darker place. Finally I reached the limit of the Nikon D4 which managed to achieve focus about every second time at 300mm in a situation that was about 3 stops darker than the limit of the 1DX. Same kind of subject and same histogram.

It is now clear to me that the autofocus in my EOS 1DX is way behind the one in my Nikon D4 in very low light

I repeated the test with various subjects with different contrast and the result varied slightly but immediately it was clear to me, that the autofocus in my EOS 1DX is way behind the one in my Nikon D4 when it come to low light scenes – and here I mean really low light. Not only do the Nikon D4 lock on the subjects in more darkness it also works equally good in S and C (One Shot and AI-Servo). Because of that I always use the C mode and then the AF-lock for non-moving subjects.

Well thats all from now. I hope you guys can understand my English and I hope you may find some of this useful. I am new to this Canon EOS 1DX so if any of you have any inputs that I may benefits from, I would really appreciate your comments on my Facebook page.

All the best
Morten

Test of the Canon EOS 1DX autofocus in low lightTest of the Canon EOS 1DX autofocus in low light