View Full Version : sinar extension with 210mm

Serge J-F. Levy
25-Apr-2005, 16:42
I have a sinar x with a standard rail on it. I recently purchased a 210mm and I will be shooting some close range( i.e. 1-2ft focus) photography. Does anyone know what size extension rail I will need to purchase? Also, are all the sinar extension rails interchangeable?


John W. Randall
25-Apr-2005, 19:26
Get your measuring tape out; it helps sometimes when you are trying to make sense of how advertised rail lengths are expressed versus what the usable length is. The standard black Sinar rail has an effective usable length of about 9 1/4th inches, or 235mm. The "6 inch" extension has a real usable length of about 5 7/8ths inches, or 150mm. The "18 inch" rail has a usable length of about 16 inches, or a bit past 400mm.

If you are aiming for 1:1, where the image size is going to be the same as the subject size, you will need 420mm of usable rail - more would be better for getting in as close as it sounds like you want to focus.

You will also need to extend your bellows to make this all work - and the only way I know to get this done with Sinar is to purchase another bellows, and an intermediate standard, to extend to the length you want.

Another way to capture closeup images with lenses of this or similar focal length is to cheat: Purchase a Canon 250-D 2-element close-up lens and attach it to the front of your 210mm. This will reduce the need for such a long bellows setup, and can actually save you from bellows light-loss issues, which, of course, will occur with long bellows extensions. You'll need some extension - just not nearly as much.

Hope this helps.
Best regards,

John Gittens
27-Apr-2005, 16:23
Hello Serge, If you have a shorter focal length lens you can still use it to get 1:1 image size and you will not necessarily need a longer rail or bellows extension. Many years ago I needed to take a picture of a dried Lima bean for an Ad. and did not have the equipment I have now. With the standard Sinar I had then I used a 90mm. wideangle lens with the bellows fully extended and got an almost full image of the bean - but you still have to compensate for bellows light loss unless you have a Horseman TTL exposure meter!.