For the two weeks we have been in Oregon I have spent a lot of time going over our photos from the Australia trip. You guys know how this works, take more than 8000 frmes and find the twenty good ones. One thing that has bugged me this time is that I had less than desirable results with the 100-400 lens. Actually I was quite disappointed with the whole thing. I had read about people claiming it was soft. If you have one, I would like to hear what you think. I don't think it's soft, I think that it has to do with depth of field (DOF).
Anyway, for the last couple days I have been reading up on DOF. This can be pretty slow at 49.5 kbps. I found a very handy DOF calculator at: http://www.dofmaster.com/dofjs.html that has been very instructive for me. The photo for today was the one where the light came on in the attic for me. You will notice that the duck in the background is prety much in focus, but the one in the foreground is not. One thing I also discovered in the last couple days is that the EXIF data includes the subject distance. Cool, but a limitation of that data is explained later. I plugged in the subject distance (18 meters), an f-stop of 8.0 and focal length of 400mm and found the depth of field under those conditions was 95 cm (please note the facile use of metric measurements. Not bad for a colonist!) That is pretty damn narrow in my view. I had never bothered to check that out in the past and as a result I have learned something useful.
When we were on the Yellow Water Wetlands boat cruise amid tons of neat critters, I was clicking merrily away with the 100-400 and not paying too much attention to my settings. As a result, I ended up with a lot of poor shots, not just due to DOF. Even with IS, you have to keep the shutter speeds up because the subject might be moving. The one thing that I always forget also is that the 5D Mk2 body has outstanding noise performance, and I just need to push up the ISO and in so doing cut myself a lot of slack.
Not sure about you guys, but I usually cruise around with the camera set in aperature priority with f/8 and adjust the ISO to get the shutter speed I want. With short subject distances at 400 mm focal length you really gotta be on your toes with respect to DOF.
This has been a learning experience. I like to have those at least once a year. I started to go back to my aircraft photos and found out a little problem working with them: the EXIF subject distance data. It apppears that the numbers make a big jump from 80 meters to infinity with nothing in between. I have searched around for lens data that would give more information about that piece of EXIF data. If you know something about it, let me know.
So why the bitching and moaning about the lens being soft? I think people get buggered up with DOF limitations. At 400 mm and relatively short distances, one little flub in where the lens sets its focus can set the focus at the desired subject off a bit, giving a soft look. As I look at photos where the subject looks soft, I can often see other bits that are sharply focused. This photography jazz is all about technique. Also composition, story and lighting, but that's left for another day.
My son Robert shoots M all the time. I like the focus range switch on the 100-400. Most of the time I keep it set to the longer range. I seldom shoot less than 6.5 meters with it. I thought in Mode 1 it was supposed to sense panning and revert to mode 2. I set it in mode 2 whenpanning anyway. I use aperture priority most of the time because I like f/8, which is supposed to be the sharpness "sweet spot" for most lenses.
Well, I'm a odd ball...I keep my cameras set on "M" manual at all times and have them set to focus with the center target only. I don't like the camera doing changes without me 8-)
One thing you might want to play with on the 100-400 is the AF range switch and mode 1&2/off IS setting (off using a monopod/tripod of course).
BUT... be sure you reset to what you want up first next time out before you put it away. Would be nice if these settings would show in the viewfinder.
Wish you could buy these cameras with "a la carte" pricing, I could save a bundle.
I always like to hear what others are doing.gets me off my duff to try something different. I has actually stopped raining here and I am going outside to fool around with my camera, oops, try to be creative. Aw hell, let's be honest, I am going to screw around with my camera.
Would that be gas meters, electric meters or distance metres.
Anyway, I will get Professor Morrey, Emeritus to translate this into English for me (no metric here).
My standard carry set up is with the Canon 70-200 f4 IS lens, set to P on the program wheel.
WB set to auto, ISO set to local conditions, centre square focussing, partial metering, and AI servo.
Possibly 80% of my shots are taken like this.
Possibly 90% of those shots are taken quite fast, swing up camera, start pressing shutter
before the camera is pointing at the subject, keep pressing shutter until subject aint there, or I think I have a good shot.
This works very well for me, and occasionally I get some good shots.
Because the power of the zoom is low, my subjects are usually within DOF limits so I dont have to calculate what it will be.
I usually try to get the subject as perfect as possible, not worrying about the background at all.
The smaller percentage of my shots is where I am learning photographic techniques, I am a slow learner at this and dont have enough years left to perfect them.
I absolutely love taking photographs, it is a great pastime.
PS facetiousness apart, I do read and try to understand your reasoning, and hopefully learn something more.
