drdale

I do a lot of macro work with multiple exposures with a series of focal points. Even when I use a series of 10 shots there are areas that are fuzzy when the layers are put together. Given how many shots are taken at F8 and the very small adjustments of the focal ring this does not seem right. Any ideas?

tradio Loc: Oxford, Ohio

I thought you focused by moving the camera, not adjusting the focus ring.

drdale

I know that is an option if I had the equipment to do that, which I don't.

SonnyE Loc: Communist California, USA

Hi drdale.
I'm barely beginning in Macro myself, so take this with a grain of salt...
But some of the "Stackers" I have encountered do much greater stacks, like as many as 36 shots, and 1mm focal changes on a macro rail.
So my thought is, try much higher number stacks, and much finer focal length changes.
Make sense?

Also, you will likely get much better help in the Macro Forum.

http://www.uglyhedgehog.com/s-102-1.html

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

Use a focus rail & move the camera, not the focus ring....Moving the focus ring changes the subject magnification...

drdale

Suggestions on where to buy a "focus rail"?

drdale

Hello again.

I just realized I can take apart an old Vivatar Bellows and turn it into a focus rail. Thanks for the suggestion. I will try this.

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

B&H, Adorama, eBay, et al all have them at varying price points. I do little stacking, so I just got a cheapo off of eBay...

tradio Loc: Oxford, Ohio

Please post your results!

drdale

I tried both approaches on the same picture. The rail trial did not turn out so well. The problem is that as the camera moves in the image is framed differently and parts even go out of the frame. When all the layers get put together there are ghost images that are just all fuzzed out.

Apaflo Loc: Anchorage, Alaska

Don't take a Vivitar Bellows apart to make a focus rail! Those are a pretty decent bellows, and can be found every few days on eBay for less than $30. There is a Vivitar Focus Rail made specifically for it! And they usually either come with the bellow or are separate for less than $30. Nice combination, if for no other reason than it has T-Mount threads at both ends, and adapters are available for almost any combination of cameras and lenses.

Focus stacking can be done by moving the focus ring on the lens, or by moving the entire camera. As noted previously there are different effects from each of those methods. The best way though is to use a bellows and a focus rail, and make the increments by changing the camera to lens distance while keeping the lens to subject distabce the same. That greatly reduces the artifacts that stacking software has to deal with from changes in framing and magnification over the range of the stack.

Your described problem does sound as if the focus change increments in your stacks are too large. If your DOF is, for example, 2 mm and you move the focus by 4 mm each time it will put a band of out of focus area in between each in focus area. But if instead your focus increment is 1 mm, half of what is in focus in each shot will also be in focus in the next shot too. That will eliminate the artifacts. An increment of about 1/2 the DOF it leaves a lot of room for sloppy increments too.

Incrementing by hand is certainly possible. It is very difficult to get even increments with a lens focus ring though. And given that a realistic stack may be anything from 12 to 512 images, it's a tedious job at best. A motorized stacker like StackShot is nice.

oldtigger Loc: Roanoke Virginia-USA

An inexpensive manual screw operated rail with a $10 caliper taped to it makes a great learning tool and will do anything the big boys do.
25 frames, overlapped 50% on a subject parallel to your sensor and moving the camera not the focus, should give excellent results.

Erik_H Loc: Denham Springs, Louisiana

Another thing that you could try is stopping down to about f/16 to squeeze out a little more DoF.

drdale

All good ideas. I may have to wait until next year for Santa to bring me a Stackshot though.

I am still wondering where those ghost fuzzy images out away from the subject are coming from though. Issue with the lens getting closer and frame changing I guess.

JimH123 Loc: Morgan Hill, CA

What stacking SW are you using? The better ones accommodate the changing size and perspective of the target as the camera is moved. And I suspect there are some that cannot do this.

A focus rail is the best way to do this. At very short distances, focusing by moving the camera is the most controlled method. Turning the focus ring is not controlled at all. You can't predict where your focus range is going to be. And it may be a fairly narrow sliver that you get, unable to accommodate the entire object on interest..