Modify bellows to move body with a Stackshot

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kpassaur
Posts: 22
Joined: Tue Mar 24, 2015 6:52 am

Modify bellows to move body with a Stackshot

Post by kpassaur »

I have read in a couple of places that ideally you want to move the camera body to focus while leaving the lens stationary. I haven't tried it but I was thinking of making an automated rig to do it.

First, does it actually work better? and second has anyone modified a Stackshot to do so? On ebay I found a cheap bellows that by the looks of things can easily be modified to mount to a Stackshot. I would just need to make two small brackets, one to attach to the camear mount and the other to the end of the Stackshot. The Stackshot would then be the bellows rail.


If someone has done this or has any ideas on it please let me know.

JohnyM
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Joined: Tue Dec 24, 2013 7:02 am

Post by JohnyM »

Yes, it works better. But trade off is that it changes DOF while moving, so you need to stack a lot more frames.

rjlittlefield
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Post by rjlittlefield »

JohnyM wrote:But trade off is that it changes DOF while moving, so you need to stack a lot more frames.
That wording, "a lot more frames", seems way too strong.

We've worked through the numbers on this in previous postings, such as http://www.photomacrography.net/forum/v ... 796#192796 .

Even for extraordinarily deep stacks, like from 1:1 to infinity, the penalty for using fixed size steps is only about 2X, compared to a perfectly optimal strategy that would use variable sized steps at a fixed aperture setting.

For shorter stacks, the penalty is less, tending to 0% in the limit. For "typical" stacks, pulling a number out of the air, I'd guess a penalty closer to 10%.

kpassaur, can you tell us a lot more about the sorts of stacks that you intend to shoot? I am particularly interested in physical dimensions of the stack (width, height, depth) and what magnification you would be shooting at.

--Rik

kpassaur
Posts: 22
Joined: Tue Mar 24, 2015 6:52 am

Move Camera Body Only with Stackshot

Post by kpassaur »

I made it and did a couple of test shots. It took a couple of tries to get it right. At first I made a mount from the bellows to the StackShot and it was a pain to but it on and the weight of the camera made it sag. So, I did it over and now it goes on and off easily and it is not difficult to align. You just mount The camera to the StackShot, compress the bellows then hold it in place and tighten the thumbscrews.

I have only done a couple of test shots and I am not thrilled with my results. This could be because of other factors such as the subject, lighting etc. I don’t quite think the sharpness is as crisp as it normally is; however it is too early to tell. It is simple to make and it cost next to nothing. The bellows is $20 on ebay and I had some small scraps of metal in my garage, but even if you had to buy them I don’t think they would cost more than $5.


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ChrisR
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Post by ChrisR »

You could take that a bit further, with an appropriate lens.
Do a search on "Olymincan". ;)

Check the 4th pic here:
http://www.photomacrography.net/forum/v ... hp?t=10276
Chris R

GrayPlayer
Posts: 58
Joined: Sat Nov 14, 2009 5:44 pm

Post by GrayPlayer »

Wondering if a focus rail could be attached to the front of bellows. Purchasing a bellows and worried about the front hanging in thin air and having a tendency to bounce.
Last edited by GrayPlayer on Wed Feb 20, 2019 4:40 pm, edited 1 time in total.
Fred H.

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