ron chappel
5th of June 2005 (Sun), 08:55
I've seen this done before and discussed on this forum using another model lens
but i thought some might be interested in the results i got by experimenting with the early EF 35-70/3.5-4.5
It seems to work very well at this.
If i remember rightly ,the guy who first tried this used a 35-80 lens (?) and it only worked at one zoom setting (i think.....could be wrong).
Of course the advantage of using a chopped EOS lens is that the auto aperture still works :D which makes it so easy to do macro
It even has focus confirmation!
I did exactly the same modification as the earlier experimenters by removing the front element group.
Interestingly this model worked at all zoom settings,varying the magnification ratio as it zoomed.
This is what the lens looked like without it's front....yeah horrid pic .I'll try to take a better one later:oops:
http://gallery.photo.net/photo/3427134-lg.jpg
Here are some rough examples i just took
The ruler is marked in millimeters so the magnification it gives is quite strong! It gives good sharpness but has pretty strong field curvature.
Stopping down cures the field curvature-and one generally needs small apertures for depth of field in macro anyway
Note that the top right and bottom right pics are blurreir than they should be-both have some movement blur
http://gallery.photo.net/photo/3427081-lg.jpg
If anyone wants to try it with this model lens,here is the way to access the front element screws.
They are hidden under the front plastic lens surround-just pry it out with a small screwdriver (note this pic doesn't show the whole lens!-just enough of the front parts to show where to get in)
This model is a little more complicated than most but i won't try to explain much more of what's inside.It's best if you have a look and see i think.It should be dead easy to take apart-it's just the putting back together that maight take some trial and error;)
http://gallery.photo.net/photo/3427142-lg.jpg
I'd be facinated to see how other model lenses work but don't have any others handy at the moment.One thing that will certainly restrict some models is that as the focal length is increased the magnification gets stronger-but the working distance gets shorter too.
With longer focal lengths this just can't work because the lens elements would be touching the object you want to take a pic of but it still wouldn't be close enough to focus!
but i thought some might be interested in the results i got by experimenting with the early EF 35-70/3.5-4.5
It seems to work very well at this.
If i remember rightly ,the guy who first tried this used a 35-80 lens (?) and it only worked at one zoom setting (i think.....could be wrong).
Of course the advantage of using a chopped EOS lens is that the auto aperture still works :D which makes it so easy to do macro
It even has focus confirmation!
I did exactly the same modification as the earlier experimenters by removing the front element group.
Interestingly this model worked at all zoom settings,varying the magnification ratio as it zoomed.
This is what the lens looked like without it's front....yeah horrid pic .I'll try to take a better one later:oops:
http://gallery.photo.net/photo/3427134-lg.jpg
Here are some rough examples i just took
The ruler is marked in millimeters so the magnification it gives is quite strong! It gives good sharpness but has pretty strong field curvature.
Stopping down cures the field curvature-and one generally needs small apertures for depth of field in macro anyway
Note that the top right and bottom right pics are blurreir than they should be-both have some movement blur
http://gallery.photo.net/photo/3427081-lg.jpg
If anyone wants to try it with this model lens,here is the way to access the front element screws.
They are hidden under the front plastic lens surround-just pry it out with a small screwdriver (note this pic doesn't show the whole lens!-just enough of the front parts to show where to get in)
This model is a little more complicated than most but i won't try to explain much more of what's inside.It's best if you have a look and see i think.It should be dead easy to take apart-it's just the putting back together that maight take some trial and error;)
http://gallery.photo.net/photo/3427142-lg.jpg
I'd be facinated to see how other model lenses work but don't have any others handy at the moment.One thing that will certainly restrict some models is that as the focal length is increased the magnification gets stronger-but the working distance gets shorter too.
With longer focal lengths this just can't work because the lens elements would be touching the object you want to take a pic of but it still wouldn't be close enough to focus!