Three days of shooting with 7D-AF performance and IQ
Following up on 7D IQ and AF performance, this weekend I went shooting Cali raptors with Oliver Klink in Half Moon Bay area, weather was quite nice and raptor activity was high we got many good photos. I also took the camera for for a shoot on Friday to Palo Alto Baylands in order to evaluate the new AF system with shore birds.
First the positives, the camera is very well built, it feels professional and chunky as opposed to the hallow feel of 50D and 5DMKII. It has a soft shutter release which makes it feel faster and more responsive, controls' layout is very good and the addition of the new CF-n button is welcomed. The IQ of the new camera is also good, when shotting in RAW mode and processing with Canon DPP, files are cleaner in terms of both chrominance and luminance noise compared to the 50D, when inspected at 1:1. The noise pattern is tighter and easier to clean up, it is not as good as a full frame camera but certainly good given its tight pixel pitch.
As for AI-servo tracking performance, I tried all the possible permutations on Friday, taking about 600 frames. Results were somewhat mixed, sometimes the photos were OOF for no apparent reason. I took the 7D to the raptor shoot as my main flight camera paired with my 400 f/5.6L. The camera was used in the field two full days in a row with about 2K shots. the camera seems to lock very quickly, however the percentage of sharp photos was unfortunately very low, even in good light and moderate tracking situations. We used single AF, spot AF, and AF expansion mode, C.Fn III-1 was set to slow and slow+1C.Fn III-2 was set to 0 (forcing focus priority rather than drive speed) and C.Fn III-3 was set to 1 (tracking priority to avoid AF being fooled by FG/BG foliage). After reviewing the images I suspected something was wrong with my lens or hand-holding technique although I was able to get much better results hand holding a much heavier rig that I had brought for tripod shots of perched raptors. The next day I gave the camera to Oliver to try it with his 400 f/4 DO and 500 f/4, both lenses produce very sharp flight images with a 1DS MKIII. Again different permutations of AF-expansion mode, single AF and spot AF were used. Looking at the morning images, again the percentage of sharp images was very low and upon comparing single-shot with AI-servo shots of perched raptors we concluded that the expansion mode AF has no particular bias on the selected center point and has a tendency to randomly lock on BG, or any other point it wishes. In the evening we tried spot AF and we got mixed results, again some shots that should have been nailed instantly were completely OOF. We also tried single AF point with spot sensors disabled and no expansion, while things improved a for birds against clear BG, camera had instability holding focus on stationary subjects as well as tracking against busy BG. I am including some samples here. I did a quick search on the internet and I found another bird shooter reporting similar lock on the BG issue.
but I am not sure how credible this is, nevertheless I am recommending people who have not bought the camera yet to hold their order until more people evaluate the AF performance. I am also calling CPS tomorrow to figure what they have to say. I would be interested to hear what other 7D owners have been getting in the field.
These are a few shots from a sequence of 35 shots, there are no in focus frames in this sequence.
There were tens of sequences with very few or no critically sharp images, this is a sequence of 20
Harries are very challenging as they abruptly dive and bank in a random pattern, however I do expect to get some sharp photos in a sequence, at the same time the above sequence was taken I also tried a much heavier rig which included a zoom lens and a TC (not the ideal case of tracking) and I was able to achieve a good number of very sharp images.
Reply With Quote
Originally Posted by Kiran Khanzode
