Whilst I have had some reasonable pictures with the 7D I haven’t been totally satisfied with the results. At first I thought it was my technique that was wanting because the lens I purchased (Canon 400mm f5.6) does not have IS. I had also read somewhere that the 7D requires a heavier hand on the sharpening to get the desired results and indeed I have had to resort to this on most of the images I have posted on Flickr. Whilst heavy sharpening can often improve the image the results are never the same as a picture that started off sharp and heavy sharpening increases the noise quite markedly .......... but that’s another problem.
A month or so ago on a rainy day with the Slavonian grebe in Dover marina I did a side by side comparison of the Sony and the Canon and without doubt the Sony was the best. As I'd only just got the Canon I attributed this to the lack of IS on the Canon and the slow shutter speeds I was experiencing.
On one of my days on the cliffs with the perched peregrine I did another side my side comparison and on this occasion although the Canon produced the superior images I was still a little disappointed with the results especially when cropped in close. As before there was a softness to all the images even though this time the pictures were all were taken using a tripod and I had good shutter speeds.
The outcome of these comparisons and problems made me reluctant to take the Canon out on dull days and if/when I did I was resigned to using a tripod and high ISO (to keep the shutter speed high).
Having spent so long in deciding what to buy to replace the Sony I didn’t want to admit to making a mistake in purchasing the Canon - not just because of the money wasted but because I had no idea what to change it for. So had I wasted my money? Today I set out to find out.
My first test on the accuracy of the focusing was to use a method suggested by Steve Ashton whereby you set up at ruler at 45 degrees then focus on one of the central numbers. I took a number of shots at different shutter speed and every single one suggested I had a front focusing issue i.e. the number I was focusing on was not the sharpest it was several centimetres down the ruler..
I searched the internet and found a test target (published by Tim Jackson) that I printed off, set up and ran some more test. The test chart is marked up to show how bad the back/front focusing is - with the right hand side being further away from the camnera This test showed I had a significant front focusing problem - of the order of 10-20mm.(I did a lot of shots at different shutter speed but I needn’t have bothered – they all showed the effect):
|Focus was on the thick black line|
Out with the manual and after several changes to the autofocus microfocus adjustment I think I have overcome the problem:
Sunday. As the sun was shining I went along the cliff tops from South Foreland to Langdon Hole looking to find something to point the camera at (hoping for a peregrine) to test whether the adjustments would have an effect in the field.
There was a not a lot going on but mippit numbers have increased over the last few days and were singing/displaying with gusto but the first test subject was a male stonechat. He never let me get really close but the results were far far sharper than I had grown to expect (I’ve put an uncropped version up so you can see the level of cropping done on the close up):
When at Langdon Hole I spotted 2 peregrines circling just above the cliff top back towards Fan Bay so I returned to near the rock fall and waited. I didn’t have to wait too long before one did several passes:
Whilst waiting for the peregrine to come close one of the herring gulls seemed to take exception to the presence of the peregrines and pestered one of them for about 5 minutes but sadly always distant:
|Herring gull attacking peregrine|
On the return leg there was a male wheatear down in Fan Bay but I couldn’t be bothered to climb down to try and get some pictures but a mippit did let me get reasonably close and again the shots are much better than I’ve experienced previously.
So not an exciting day bird wise but it’s a relief that the camera is now operating how I’d hoped it would.
(Click on any image to get them all at a larger size)