Reversed Lens Aperture Control

Kevin Childress · Post by **Kevin Childress** » Thu Aug 20, 2015 12:40 pm

Today I received this aperture controller for use with my Nikon 50mm AF-S f/1.8 lens. For the price this is a fantastic piece of equipment for quality, machining, finish, etc. But now I need to put it to use ...

Obviously the adapter has no f/stop markings or lines on it, which would need to be worked out for whatever lens its attached to. The outside of the adapter has nice knurled lines marked all the way around. The recesses of the knurling make great straight lines for marking the adapter ring with f/stop (call it white paint in the recesses). But I can't decide how to transfer the f/stop lines from the adapter to the lens. A sharp engraver seems like it may do the trick but I'm hesitant to take that step.

Does anyone have a similar piece of equipment that you've marked corresponding f/stops between the adapter and lens? Can you share an image, please?

Thanks!

Kevin

ChrisR · Post by **ChrisR** » Thu Aug 20, 2015 1:41 pm

Could you screw an empty 52mm filter on the front and scratch that?

elf · Post by **elf** » Thu Aug 20, 2015 5:19 pm

Fingernail polish might work for you. Acetone will remove the polish if you decide you don't like it, but it may also affect the plastic on the lens (that is if the lens is plastic).

You can also buy paint tubes with built in applicators.

Chris S. · Post by **Chris S.** » Thu Aug 20, 2015 6:32 pm

elf wrote:. . .(that is if the lens is plastic).

From the descriptions of "All metal design" and "Anodized black finishing," it appears that the device is anodized aluminum. (The couple of items I have that are made by Fotodiox are anodized aluminum, and very well made.)

Another possibility for marking the knurls might be enamel paint applied with a fine brush. I'd suggest making the first marks with thin strips of tape, which could be moved around until you get them where you want them.

By the way, only the newer "G" series Nikon lenses require this sort of device for reverse mounting. Some of us suggest that the G stands for "gelded," as it indicates that the aperture ring has been omitted from the design. There are tons of very nice, earlier Nikkor lenses available that have proper aperture rings, at prices sometimes not much greater than this Fotodiox adapter.

--Chris

Kevin Childress · Post by **Kevin Childress** » Fri Aug 21, 2015 5:34 am

elf wrote:Fingernail polish might work for you.

Possibly, but I wouldn't be able to apply that in a sharp enough line. There are roller-point paint markers that should work. Thanks for the suggestion.

Kevin Childress · Post by **Kevin Childress** » Fri Aug 21, 2015 5:52 am

Chris S. wrote:I'd suggest making the first marks with thin strips of tape, which could be moved around until you get them where you want them.

Good idea. I know it will take a little trial and error. I have just the tape for this.

Chris S. wrote:There are tons of very nice, earlier Nikkor lenses available that have proper aperture rings, at prices sometimes not much greater than this Fotodiox adapter.

I bet you're right. But I already have the adapter and I'll learn quite a bit through this process so that's okay with me.

I realized something this morning that I didn't notice yesterday. The forward-most section of the adapter doesn't rotate with the ring. So that's a good surface to transfer the stop lines to rather than the lens body. Here's an image of what I have in mind. I probably won't have room to write the stop numbers on that surface, but the dots should suffice - with a little cheat sheet for reference.

ChrisR · Post by **ChrisR** » Fri Aug 21, 2015 6:49 am

OK, a knurled 52mm filter ring!
Or a step-up ring, then you could fix a pointer to it!

Kevin Childress · Post by **Kevin Childress** » Fri Aug 21, 2015 7:14 am

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!

ChrisR · Post by **ChrisR** » Fri Aug 21, 2015 5:35 pm

I just remembered a "proper" Nikon ring is a BR-6 (Nikon F female to 52mm female), which you could use with a cable release.

A BR-4 ( F make to F female) would work if it cleared the AF contacts. Some do, some don't.

Yours is cheaper though.

Kevin Childress · Post by **Kevin Childress** » Sun Aug 23, 2015 4:00 am

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 to get a rough feel for making adjustments and it dawned on me that I only needed one line or dot out front. The good news: My first round of tests has been very positive and I am seeing sharper pixels by stopping down the reversed lens instead of the main lens. The 5 lines you see on the adjusting ring represent the full range of the lens' aperture (f/1.8 - f/16 in normal use). I measure the total range of rotation at only 6.5mm so I'm working within a fairly tight range. The middle line, or 'line #3', is producing the sharpest images so far.

The light I was using was AC power continuous light that I would use in some macro projects. With that light I'm seeing a consistent 1 2/3-stop gain on the camera's exposure meter when adjusting to the 5 lines you see. I want to tighten that up to consistent 1-stop increments so I might end up with ~8 dots or lines by the time I'm done which is a lot for a 6.5mm window! Practically speaking, I'll then find the 'sharpest dot' and use that moving forward.