EOS 20D with Carl-Zeiss 50mm f/2.8 lens & Bellows

[BlueTit]

From posts here and elsewhere I finally decided on and bought Canon 100mm 2.8 for macros. While I was deciding I bought an old bellows type macro lens with EOS fit on eBay. I didn't get to try it until today when MT-24EX arrived. I don't know how the thing works - I have never used film, but it is amazing. These were very quick shots without a tripod, but look at the detail - they are all uncropped. It is a pencil sharpener, a very old one.

With the bellows at maximum about 22cm:

http://photos8.flickr.com/10890348_cad2fb4bc7_o.jpg

With the bellows fully retracted:

http://photos5.flickr.com/10890349_12030ff6ce_o.jpg

The closest I could get with Canon 100mm F2.8 USM

http://photos8.flickr.com/10895468_45aad2c2a5_o.jpg


Anyone know how to relate the scale on the bellows rail to the magnification? Be very interested to know what magnification this thing is capable of.

[gasrocks]

Magnification ratios are based on 35mm negative/slide which is about 1" X 1.5". Life size 1:1 means that area fills the frame. Want to know what "power" you are at with any macro set-up? Look at a ruler (through the viewfinder - ok, not all viewfinders are 100%, but close,) and do the math. Ex: is frame is filled by 2" by 3" area you are at 1/2 lifesize. Make sense?

[Jon]

Magnification ratios are based on 35mm negative/slide which is about 1" X 1.5". Life size 1:1 means that area fills the frame. Want to know what "power" you are at with any macro set-up? Look at a ruler (through the viewfinder - ok, not all viewfinders are 100%, but close,) and do the math. Ex: is frame is filled by 2" by 3" area you are at 1/2 lifesize. Make sense?

No. 1:1 means that a 1" subject will yield a 1" image on the sensor. It just happens that in 35 mm, an image at 1:1 will cover about 1x1.5". If the scale on the bellows shows close-up ratios, they're going to be the same on your camera as they are on a full-frame 35 mm camera, assuming the same lens (no cra^hop factor applied). Macro's one place where you ignore the cra^hop factor.

[BlueTit]

Thanx. The scale on the belows is mm, it ranges from 90 to 290 and I assume it measures the distance from the lens to the sensor, though this was made when film was the only format, so it would not be the same for all cameras, depending on the location of film / sensor.

I took a shot and filled the width of the frame with 4.75mm of ruler. So do I divide that into the sensor width to calculate magnification factor? I don't really care what it is, it is just as a matter of interest. I is really amazing for £80 worth of kit. :lol: :lol:

Interested to know what macro fans photograph at this scale, I am running out of items of interest, have tried sugar, salt, clay, tobacco and our smallest coin the 1 Euro cent, about a quarter of the coin fills the screen!

[Jon]

If the scale's in mm, it'll be to the focal plane of the camera the bellows was designed for. Whether it apples to just the bellows or the bellows + lens, depends on a number of things. My old FD bellows had a scale which gave mm to the front standard, and a magnification table for the 50 and 100 mm macros.