Closing the loop (for now at least) ... I spoke to Savage about the tube keeping the aperture stopped down all the time. They commented on having seen a few issues where the tube wouldn't "click" into place on the lens but they didn't seem to want to discuss reports of an overly tight fit to the len...

NikonUser wrote:117 mm exension tubes behind the Nikon 105 gives >2:1 magn. with min. vignetting

NikonUser, right on. I've been testing recently with 71mm of extension and that's getting me 1.9x and my vignetting looks practically just like on your grid paper.

Unfortunately it sounds like that particular model of lens has its entrance pupil far backward. Indeed, the diaphragm is set back a ways from the front of the lens. As Enrico says, the best bet is usually to have the rear lens wide open and focused at infinity. That usually pushes the entrance pupi...

This 105mm lens seems to be a bit of a problem child with vignetting - I've had someone ask about it on my site too in the past and I've seen the vignetting on other shots using that lens. I've seen it be more successful though with both lenses wide open, maybe give that a try. Thanks for the reply...

Enrico, Thanks for all the input. A few ideas below ... The general suggestion is stopping down the front (reversed 50 mm) lens and leaving the rear (105 mm, normally mounted and usually focused at infinity) lens fully open. From your description it sounds like you are doing the opposite. If you sto...

I wanted to share an experience I've had using a reversed Nikon 50mm f/1.8 mounted to a Nikon 105mm f/2.8 micro. I've always thought that using a reversed 50 was one of the more common alternatives to increasing reproduction ratio but I've never heard this issue mentioned using a setup like this. I'...

Rik, Pau, and Chris, Thanks to you all for the help. I felt like an idiot as soon as I read the first replies here. I should have realized the problem when I shot those other f/stops and didn't compensate for exposure. So yeah, the aperture is staying stopped down - all the way down - all the time. ...

Rik, I'm not sure what you mean about checking the exposure time. I mean, I know all the images shot with the extension tube were at 1/250th, but not sure what else there is to know about it. Your idea about the lens being stopped down all the way, all the time, is as good of an explanation as I can...

Looking for help to understand a problem with image quality. I'm shooting a D810 with Nikkor 105mm f/2.8 micro. The extension tube is a variable tube (55 - 71mm) from Savage and seems like a very well built piece of equipment. I used the tube at 55mm and noticed right away the extension tube dramati...

At the heart of my macro photography is my "macro table" - a piece of equipment originally designed for photographing 35mm film slides. I adapted this table to my macro setup because of the precise control it offers for X and Y axis adjustments (see the two adjusting screws on the rear and right sid...

At the heart of my macro photography is my "macro table" - a piece of equipment originally designed for photographing 35mm film slides. I adapted this table to my macro setup because of the precise control it offers for X and Y axis adjustments (see the two adjusting screws on the rear and right sid...

Yesterday I posted a question discussing how one might create a bokeh effect with macro backgrounds. Clearly I already had an idea of how I wanted to attempt that by punching holes in background paper and back-lighting the holes, so I refined the approach a bit and here's what I got. I mostly got wh...

Despite that I am primarily discussing bokeh here, I would appreciate any tips you have for creating more interesting backgrounds for macro images. For me creating interesting backgrounds for macro is definitely the most difficult aspect of the entire process. As such my backgrounds are typically bl...

I completed my first round of tests with this aperture controller and I may have to forego the idea of marking the adapter with literal/accurate f/stops. The mathematical approach is just beyond me so I won't be marking the adapter with any numbers at all. In my testing I was using marked tape just ...

ChrisR wrote:Or a step-up ring, then you could fix a pointer to it!

Yep, I'm actually looking at a step-up ring right now!