Narniaman
2nd of April 2005 (Sat), 23:35
I need someone to tell me why this is a bad idea.
First, some background. About three years ago I got a Sony F707. For telephoto help, I purchased an Olympus B-300 1.7 teleconverter and an adapter. I thought the combination worked quite well.
About a month ago I decided to make my move to the big time, and bought a Canon EOS 20D and a Canon EF 75-300 Imaged Stabilized Ultrasonic focusing telephoto lens. I have extremely pleased with the 20D and reasonably pleased with the 75-300 lens.
Among other things, I use the camera to take pictures at my daughters softball games (talking about major college softball here). When taking pictures beyond the outfield fence, I have felt that I would like just a little bit more focal length than 300 mm -- I can get a reasonably good shot of the batter and catcher, but it could be a little bit better. So I took a look at the L-series 70-280 f 2.8 lens and the 100-400 f 4 lens -- which retails for something like $2000 and $1600.
I took a series of pictures with both lens and compared them with the EF 75-300 lens, and decided that while the more expensive lens gave better pictures, they weren't a $1000 dollars better pictures.
While pondering over what to do, I had a brainstorm. The EF 75-300 lens has a filter mount diameter of 58 mm -- which is exactly what my Sony F707 had. I figured that it would be possible to attach the Olympus B-300 teleconverter to the front of the EF 75-300, and so I tried it.
It works -- and it works almost too good to be true, so I'm trying to figure out what I'm missing.
First, since the teleconverter is attached to the front of the EF lens, it doesn't affect the electronic interaction between the 20 D and the EF lens. Autofocus still works just fine.
Second, the image stabilization on the EF lens works without problems.
Third, while the B-300 increases the focal length by 1.7, I don't take a hit in the speed of the lens. The B-300 has a large lens and a smaller lens, so the light gathering capacity in increased -- and you don't lose f-stops. In other words, the EF 75-300 f4-f5.6 lens becomes a 135-510 mm f4-5.6 lens.
Fourth, I can also use the B-300 on my 50 mm F1.4 lens, which also has a 58 mm filter ring, and wind up with a 85 mm F1.4 lens. I've tried taking some pictures with the 20D's ASA pushed to 3200, and you can virtually can take good pictures in dark rooms without any flash.
How about the sharpness? Well, I went back where I took the pictures with the L-series lens (a photo store) and snapped away. The L-series 100-400 is just a tad sharper -- but certainly not $1000 sharper.
I'm attaching a picture I took this morning from my back deck. The street sign is about 400 meters away, or about one-fourth of a mile. It's far enough away that unless you have 20/20 vision you can't see it. This is the combination working at a focal length of 510 mm. I used an f-stop of f16 and an ASA equivalent of 1600. The resulting shutter speed was 1/350th of a second.
This picture is cropped down from the original, which was about 3600 x 2400, to about 1280 x 900.
The other thing I should mention is that Canon has a teleconverter -- the TC-DC58A, which has a 1.5 power and is designed for the Canon Power G series of digital cameras. Just like the B-300, you can screw it directly onto a 58 mm lens.
Comments anyone?
First, some background. About three years ago I got a Sony F707. For telephoto help, I purchased an Olympus B-300 1.7 teleconverter and an adapter. I thought the combination worked quite well.
About a month ago I decided to make my move to the big time, and bought a Canon EOS 20D and a Canon EF 75-300 Imaged Stabilized Ultrasonic focusing telephoto lens. I have extremely pleased with the 20D and reasonably pleased with the 75-300 lens.
Among other things, I use the camera to take pictures at my daughters softball games (talking about major college softball here). When taking pictures beyond the outfield fence, I have felt that I would like just a little bit more focal length than 300 mm -- I can get a reasonably good shot of the batter and catcher, but it could be a little bit better. So I took a look at the L-series 70-280 f 2.8 lens and the 100-400 f 4 lens -- which retails for something like $2000 and $1600.
I took a series of pictures with both lens and compared them with the EF 75-300 lens, and decided that while the more expensive lens gave better pictures, they weren't a $1000 dollars better pictures.
While pondering over what to do, I had a brainstorm. The EF 75-300 lens has a filter mount diameter of 58 mm -- which is exactly what my Sony F707 had. I figured that it would be possible to attach the Olympus B-300 teleconverter to the front of the EF 75-300, and so I tried it.
It works -- and it works almost too good to be true, so I'm trying to figure out what I'm missing.
First, since the teleconverter is attached to the front of the EF lens, it doesn't affect the electronic interaction between the 20 D and the EF lens. Autofocus still works just fine.
Second, the image stabilization on the EF lens works without problems.
Third, while the B-300 increases the focal length by 1.7, I don't take a hit in the speed of the lens. The B-300 has a large lens and a smaller lens, so the light gathering capacity in increased -- and you don't lose f-stops. In other words, the EF 75-300 f4-f5.6 lens becomes a 135-510 mm f4-5.6 lens.
Fourth, I can also use the B-300 on my 50 mm F1.4 lens, which also has a 58 mm filter ring, and wind up with a 85 mm F1.4 lens. I've tried taking some pictures with the 20D's ASA pushed to 3200, and you can virtually can take good pictures in dark rooms without any flash.
How about the sharpness? Well, I went back where I took the pictures with the L-series lens (a photo store) and snapped away. The L-series 100-400 is just a tad sharper -- but certainly not $1000 sharper.
I'm attaching a picture I took this morning from my back deck. The street sign is about 400 meters away, or about one-fourth of a mile. It's far enough away that unless you have 20/20 vision you can't see it. This is the combination working at a focal length of 510 mm. I used an f-stop of f16 and an ASA equivalent of 1600. The resulting shutter speed was 1/350th of a second.
This picture is cropped down from the original, which was about 3600 x 2400, to about 1280 x 900.
The other thing I should mention is that Canon has a teleconverter -- the TC-DC58A, which has a 1.5 power and is designed for the Canon Power G series of digital cameras. Just like the B-300, you can screw it directly onto a 58 mm lens.
Comments anyone?