Macro + a reversed prime lens

[mikew148]

I was reading an article on macro photography that inspired me to purchase a reversing ring and a prime lens to attach to my Sigma 105 macro lens.

 

The article calls this - super macro photography. The only problem I have with it is the depth of field, at less than 2" from the coin, it's pretty much nonexistent.

 

Anyway, to my question. Is anybody using a good focus rail on their copy-stand? I'd like to get one with a Fine adjustment knob that moves up/down and side to side but also has an adjustment that rotates the camera and lens to get me perfectly square to my target. This limited depth of field means I need to be perfectly square to get good focus.

 

This is where I'm at. No cropping, these are the pictures as they were taken. I know the depth of field is going to be a challenge but I'm hoping a good focus rail will clean up some of the fuzziness. Thanks

 

 

 

 

[Hard Times]

Yes I use a focus rail and it definitely gives you some fine turning you can get by focusing manually with a lens. I won't image without it now that I have used it.

 

Best, HT

[messydesk]

I'm using a 2-axis Velbon focusing rail, which you can sort of see in the picture below. One axis is capable of very fine adjustment, with the knob geared like a screw rather than a gear. One complete turn is something like 2.5 mm. For high magnification shots like the ones you posted above, your best bet is to use focus stacking software (CombineZP, Zerene, Helicon, late versions of Photoshop) and make a sharp picture from 5 or so shots at different focus depths.

 

 

[brg5658]

Cool images!

 

At that level of magnification, you should look into focus stacking software. The Depth of Field will be limited almost beyond repair, but you can take 3-5 separate images focused at varying depths, and "stitch" them together using CombineZP (free), Zerenestacker (not free), or HeliconFocus (not free).

 

Type "focus stacking software" into Google and you'll find all kinds of goodies!

 

-Brandon

[Coindude]

This is what I use after Mr Messy recommended it. It works great.

 

http://www.ebay.com/itm/Focus-rail-Macro-rail-/251482732071?pt=LH_DefaultDomain_0&hash=item3a8d89f627

[mikew148]

Ok, I now have a plan. A good focus rail and some stacking software.

 

I love this place.

 

Thanks all!

[mikew148]

So I downloaded the combineZP software to see what it was like. Here's a quickie. With just 5 layers, focusing the lens manually, I was able to get the digit and the doubled digit to show fairly well. I can see how a good focusing rail, combined with this stacking software could alleviate the depth of field issues. With 10 layers, taken at precise intervals, I bet this image would be crystal clear!

 

Thanks again - Mike

 

[wdrob]

 

Looks really good. (thumbs u

 

 

[brg5658]

That is a great image Mike! (thumbs u

[rmpsrpms]

That's a very nice image.

 

Stacked lenses work well for coins. The reversed prime has a good working distance since it must work with the DSLR register (mount to sensor) distance.

 

Most focusing rails have fairly coarse adjustments, so it's difficult to get the small step sizes needed for stacks. My recommendation is to have the step size equal to half the depth of field for best sharpness in the final stacked image. Your image appears to be around 5x magnification, so you'd need around 20 micron step sizes at f/4.

 

With these magnificatiouns you're into the realm of "photomacrography". Most of the folks doing this are using various microscope stand configurations, or if they are really into it they use automated linear stages ("Stackshot" or similar). They're also mostly doing pictures of bugs, so they need "deep" stacks. Since coins are pretty flat, you rarely need more than 10 images, even for the highest quality (large aperture) lenses, but you still need to step evenly for good results.

 

 

[messydesk]

I posted this ATS, but I'll repost here. Not a coin, but cool. I have a friend who is into minerals. Lots more depth than coins, but not as many lighting issues -- until you try this:

 

 

Field of view is 320 microns wide, 90 image stack at 5 micron step using a 20x objective and a homemade robot, working distance about 1 mm. One pixel is about 430 nm (yes, nanometers). Problem is, the wavelength of red light is 700 nm. He's done a lot of other stuff that doesn't attempt to exceed the limits of visible light.

[mikew148]

I came to this community seeking knowledge of coins and have received plenty of it!

 

I didn't think that I was going to be bitten quite so hard by the photo bug however! Over the past couple of years I have taken more pictures than I had in all of my previous years combined.

 

I have found a new hobby from within this hobby and I'm enjoying both very much.

 

Thanks to everyone that has contributed!

 

P.S. - Coins, photography and golf.....I better up my retirement contributions!