OK, so we've gone considerably beyond my understanding of optics - I knew I should have paid more attention in my physics/image processing claesses. Keep us posted with some comparisons (I personally would like to see images) between what happens with different elements removed. Is there a block diagram of your lens available?
It looks like canon has deleted the image of this lens, and schematics entirely from the canon museum site. Anybody want to see hi-res jpegs of other stuff I'm shotting PM me, and I'll forward some off to ya'
I think it's pretty cool actually, lets hope canon doesn't come after me...
Not sure why thier site is down now. I have the pdf file, its basically for the lens parts. Shows the lens assembly diagram, or atleast something of that sort. They have pdf files for most of tthe canon lens.
I just picked up a 35-80mm 1:4-5.6 III. From what I've read, I'll need to take out the 3 small screws once I get the front off. The problem is that I can't get the front off.
Can someone help start me out here?
Thanks
Edited by jerseycowboy on Feb 18, 2005 at 08:09 PM GMT
Thats the same lens that I disected all you have to do to reveal the three small screws is peel off the sticker at the front that say Canon Ef 35-80 etc etc, and the screws are right there.
I had some problems with the working distance, had to keep "small subjects" real close to the lens. I will play around some more, and see if its any good taking pictures of flowers at a distance of 8" or so.
LS
I have been using the lens with and without the one element, I snap it into place when I need the working room and less magnification. Very simple, like a magnifying glass...
miraculously only cracked a couple edges, that's all, so I was able to save it. It's flat on the edge so it sits in there just fine, the only problem is if you want to take it off, you have take the name plate off and rotate the front element off... then take a microfiber cloth and just push it off... sounds comlicated but really not...
so you get the extra working distance by cracking the 2 parts of the front element ? And is that another few inches ?
I was able to get good magnification. but the subject had to be like 1-2 inches from the lens. That limited subject size being captured. I guess this makes a good macro to take pictures of tiny subjects.
Yes, it is rather limiting. I can only take pictures of tiny things. . . and of course you have to be basically on top of them to get focus. BUT, since I didn't have a macro lens before, I definitely think it's worth it....at least for me.
that one middle lens element will act as a magnifying glass, so don't throw it away... your image may become a little smaller, but you gain a few inches... I'm working on a step by step guide on how to perform surgery on this....
Thanks for the great find.
I have no 35-80mm so I tried the Tamron 70-300mm, didn't work, then I tried Canon 18-55mm EF-S, I couldn't open it using a pin, the result is my bloody fingure and a scratch on the Canon label of my 18-55mm .
Finally, I remember I got many M42 lenses. Running down to my camera closet. Found a Pentacon 30mm f3.5. very sharp lens by itself. and I believe it's cheap as well.
Open the Pentacon is a snap, very easy.
The good thing about this technique vs revered macro is you don't have dark 4 corners. and you can control DOF as you like. In addition, you can hand-held and take photos with the lens very quickly not like reversed lens macro, it's a pain in the a**
Conclusion, you may use different lenses, just try
Thanks again BellFace
Best Regards
Anh
Here are few example - ALL hand-held at ISO 1600 using my ceiling 60W light.
very interesting.... what was your working distance? I think the one good thing about using an existing canon lens, is the electronics communications stay in tact, so all the info transfers. But that would be nice to play with some old lenses...
