Sunday, 7 December 2014

A bit more on the Canon 7D mk 2

Since my last post I've not actually been out very much due to the gloomy weather and the near total lack of anything to point the camera at locally (here I am assuming there are people, less sensible than me, who are out there looking). I keep seeing and hearing comments about the mk 2 some of which are complimentary some less so, some from people who have one and some from people who don't. Here's where I am to date.

As I said in my previous post, straight out of the box the focus was clearly off and I had to do some work to sort out the best setting on the focus micro adjustment - I settled for +7. I have since adjusted that to +8 (I did this whilst photographing the great grey shrike - it wasn't moving so I had a chance to experiment in the field). It seems a few people have had trouble with the focus straight out of the box.

Noise and Resolution:
To my mind the noise is noticeably less than the old 7D to the extent that I'm happy to use ISOs above 400 with the mk 2. I have no idea just how high I can go because I haven't tried it but I have taken what I regard as decent shots at ISO 640, and 800 and reasonable shots at ISO 1000.
However increasing the ISO isn't only about noise. It also affects the resolution.
The Review by Techradar assessed the drop off in resolution with ISO setting

Using raw at ISO 100, 200 and 400 the mk 2 scores 30, at ISO 800 this drops to 28, at ISO 1600 it's 26 and at ISO 3200 it's down to 24. Up to ISO 1600 these are better than achieved with the old 7D by 2 points i.e. at ISO 800 the old 7D scores 26 but at ISO 3200 the old 7d scored the same as the new. The resolution differences are larger using JPEG but since I don't shoot in JPEG and I don't know what in-camera processing is going on I have ignored these results.

So when choosing an ISO setting I consider the shutter speed, noise and the a consequence I tend to shoot on lower ISOs and shutter speeds than I really should and hope that by taking enough shots some will catch the bird not moving. For the Chilham great gery shrike I used ISO down as low as 160 to try and maximise resolution - the bird wasn't moving so a high shutter speed was not required. Other factors that come into the equation are whether or not I'm hand holding and how close is the bird. The closer I am to the bird the more relaxed I am about choosing a higher ISO because resolution will be less of an issue.

The other factor that will impact the apparent noise level is what size of image is required. A lot of the time my post cropped images are 2,500 to 3,500 pixels wide. Reducing the pixel count to 1800-2000 (my typical Flickr size) has a beneficial effect on the apparent noise level. The extra pixels of the mk2 therefore has an additional beneficial effect on noise.


First up I must say the mk 2 is a lot qicker to focus than the old 7D.
I'm still getting to grips with the focus settings but I think I now understand what is going on. There are 2 "spot" settings and an additional 2 settings where the center spot is surrounded by either 4 or 8 adjacent focus points (called "AF point expansion" settings by Canon). In all 4 of these settings it seems that it's only the center point that actually does the focusing. In the 2 "expansion" settings it seems these additional focus points only "help", the focusing is still only done by the center point. I naively thought they were all actively focusing and couldn't understand why the outer points weren't being used when the center point had slipped off the subject (eg when in flight).

There are 2 other settings where large blocks of focus point can be selected. In these all the spots can focus and when looking through the viewfinder you can see the active focusing point jumping around. The problem with these settings is you have no control which one will be used when the shutter goes off. If you have a decent depth of field it may not matter that much but if the DOF is short the shot could still be unsatisfactory eg focused on the nearest wing tip and the head is soft.
So in general if the bird is on the ground/perched I use the most accurate spot setting. I did try the AF expansion on the snow buntings but they were rubbish and went straight into the bin. I assume the camera couldn't decide whether it was the bird or shingle I wanted to focus on.
Successful flight shots have been best with the AF expansion options though I've not tried the block options when the subject is difficult to keep the center point on (swallows for example).
Some final thoughts on this section. There were often times with the old 7D when it really seemed to struggle to get an accurate focus (for example high contrast situations or unfavourable light direction - had a lot of this with the juvenile peregrines). This doesnt seem to be a problem with the mk 2; when it has focused it seems to have been very accurate. Whilst the 7D mk 2 can shoot at 10 frames per second there are times when I think the focus is struggling to keep up with the shutter. This, to me, was a very obvious problem with the old 7D where almost every other shot was soft. It is less of a problem with the mk 2 but it still seems to be there. I can't show any examples because I delete all the shots I'm not happy with. I'll have to try and remember to keep some sequences that show this for a future blog.

Tracking Options.

Still in the dark with what's best here. Need more time. I will say the tracking even on the basic setting is superb and far superior to the old 7D and it seems to hold onto the image even when the background gets confusing (using the AF point expansion) as shown in this gadwall shot:

Shot at 1/800th sec at ISO 640

Below are some shots I've taken over the last few days with the ISO listed. I think they are not too bad. In all I have cropped in a lot further than I would normally do for my Flickr posts.
Shot at 1/200th at ISO 800
1/2000th at ISO 400 - these were quite a long way away so pleasing.

1/500th at ISO 400

1/1000 sec at ISO 400

1/160 sec at ISO 640

1/250 at ISO 640

One final thought.

With greater pixel count comes the ability to zoom in further during the processing .......and the more you zoom in the worse the picture will look (same is true for noise). And nobody zooms in as much as a bird photographer. Could it be that (some of) the softness being suggested with the mk 2 is actually down to the inherent sharpness of the lens or even the individuals ability to hold a camera steady enough as these greater magnifications..
On the former point I use the 400mm f5.6 because it's the  sharpest lens at that focal length for the price I'm prepared to pay. On the latter point people have asked me whether I will hand hold now I have more ISOs (and hence shutter speed) to play with. Simple answer..... no. I know how much worse my hand held pictures are to those on the tripod at any shutter speed. The extra ISO/shutter speed may mean I get a few more (hand held) flight shots that are acceptable but it won't change my use of the tripod. I know my limitations.

1 comment:

  1. Very informative Steve, with some very nice accompanying shots.