Best macro working distance

Started Jan 18, 2013 | Questions thread
Allan Brown
Senior MemberPosts: 1,647
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Re: Distance Scale ?
In reply to BBbuilder467, Jan 19, 2013

BBbuilder467 wrote:

Thanks for the response. That's basically what I was getting at. I thought that's how they worked. I can calculate the dimensions and distance at 1:1, but I've never seen published specs for 1:2 or 1:4.

Once I've established the 1:1, I can work with the scale on the lens. Mounted on macro rails and a tripod, I need those numbers or I can get lost. Without an accurate scale, I might as well just stay with the tubes.

I'm mounting 4-way macro rails on a 3-way pan/tilt. If I miss by a mm or two, I'm done.

Thanks a lot.

OK, I have read all the replies and I'm not sure if it is understood what is happening. If I'm wrong on that assumption, sorry.

When dealing with a lens especially a macro lens, the distance scale is only good till you get to close focusing distances. That scale then changes to magnification e.g. 1:10, 1:2, 1:1 etc. Some lenses have two scales for these functions. (yes, this is true at all distances but more important at close distances)

So, at close distances, as you change the focus on the lens, you are changing the magnification.

Now, the "proper" way to do macros, is to choose the desired magnification, set that on the lens then move the camera in and out till you achieve focus. You do not touch the focus ring. Same with macro rails.** The distance scale will not tell you much.

With close-up lenses on a tele zoom, the focus and zoom rings change the magnification but not the working distance - not on mine anyway. I use my Olympus m-con35 with my 45-200 and 100-300. In both cases, the focus and zoom change the magnification with the focus having minor effect compared to the zoom ring. The working distance is essentially constant at 25cm (this has more to do with the lens itself).

** In practice when chasing bugs, this "proper" way is less important unless you are taking the photos for scientific purposes where the scale is important.

Allan

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