learning the limits of the Sony 500 mm f/8 mirror lens
The baby eagle and I waited for two and a half hours for mom and dad to show up with something to eat. I gave up and returned home with this photo of Jr Eagle alone in the nest. As I watched and waited for mom and dad to return, I began to wonder if they just got tired of feeding him and waiting for this big guy to leave the nest and when he did not, they decided to leave the nest to him and struck off to find their own retirment home. I can think of some humans I know who should do this.
This was the best photo I got.
I forgot to bring my tripod. I had my monopod but this photo was taken hand held with me laying flat on my back. I got less shake that way. I used my 500 mm mirror lens f/8, ISO 1600, 1/1000 of a second. I pushed the picture one f stop to get the dark bird, otherwise the camera would have used 1/2000. I have included two images from the same shot. The first is a small section from the center of the total frame using the RAW image. The original frame was taken with the camera held at a 45 degree angle, simply because this was the most comfortable way to hold the camera and minimize shake. I cropped and straightened the portion I wanted in PhotoShop. The full image is the full JPG image as converted by the camera.
I was about 450 feet from the nest. At this distance I found the lens very hard to focus. The slightest movement caused the focus to move off the Eagle. Because the lens always at f/8 and I was looking at a small object as seen thru a100 view finder.
I twisted myself on the ground into a posistion where the camera was supported by my cheek bone. My head was on the ground and shake was minamal. I decided I would shot it this way and crop it and streighten later in PhotoShop.
I found myself wishing for a brighter, longer lens and a brighter view finder.
Dave
Body:Alpha 100
Sony lenses: 18-70mm f3.5-5.6 DT, 11-18mm f4.5-5.6 DT
100mm f2.8 Marco,75-300mm f4.5-5.6, 500mm f8 Mirror, 50mm f1.4



I read your thread on this.
Quite a distance from your subject here! I'd say not bad at all considering the amount of distance this lens covered actually.
I went thru the same thing when I got my Tamron 200-500. I think many do actually. The big bad 500mm badge really seems like a telescope but when you put it on your camera you realize the magnifying power isn't quite what you expected.
I'd say throw a 2x convertor on it, why not. Your lens will be rated at F13 for light transmission, but if you are manually focusing from this far away it wont hurt. Also, I recommend a tripod at this point. It will be the equivalent of 1500mm and that should give ya plenty of power.
I also heard stacking two 1.4's is better, you get more power for less light falloff.
Carl
-AlphaMountWorld Chef
~Serving up Reviews and other little Appetizers~
You've got some good patience, but the subject matter warranted it. I would say that you pushed the limits of the 500mm with the A100, considering you were 450 feet from the bird.
Royston
A100(18-70mm kit), Sigma 24-70mm f/2.8, Minolta 50mm F1.7, Quantaray 70-300mm F4-5.6
http://roystonkane.com/blog/