View Full Version : Macro Lens Vs Normal lens ?
Does a high end dedicated Macro Lens like a (Luminar or Macro Symmar HM) Need the same amount of bellows extension as a non dedicated macro lens Of the same focal length, If focused at a subject the same distance from the lens ?
cheers.
Steve Hamley
1-Jan-2010, 02:43
Yes, the only difference is that the lens aberrations are minimized at higher magnifications. And a 120mm macro lens will not, or barely cover at infinity.
Cheers, Steve
In the first view a lens is a lens. For a certain image scale (M) with a certain lens with a certain focal-lenght (f') the bellows-extention (b) is
b = f' * (M + 1)
As Steve mentioned before, every (compound-) lens is optimized for a certain image-scale.
Peter
I'm curious about this as well.
Is anyone aware of a calculator\tool that will calculate the Bellows Extension needed for a given Focal Length & Subject Distance ? My maths is not the best.
cheers
Jon Wilson
5-Jan-2010, 22:20
Is anyone aware of a calculator\tool that will calculate the Bellows Extension needed for a given Focal Length & Subject Distance ? My maths is not the best.
cheers
Check out the article in this forum:
http://www.largeformatphotography.info/bellows-factor.html
Jon
Lachlan 717
6-Jan-2010, 00:23
Watch this:
http://www.youtube.com/user/tomonator60#p/u/5/kaBnmWuL32E
About half way through, Thomas talks about bellows factor. Seems to be a pretty easy way to estimate the compensation.
Probably not super accurate (maybe not down to 1/3 stop, that is!!), but easy to get your head around.
Bob Salomon
6-Jan-2010, 03:47
If there focal length and there flange focal length are the same. then yes. If the FFLs are different then no.
If you have a dial meter (not digital) and a ruler you can accurately get the bellows extension factor without using any math. It's what I do for all my macro work.
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