Sunday, 5 August 2012

UV photography equipment researching

This morning I updated my pog website, then started a binary compare between one of my hard drives and a backup. I went to Church, then watched Kamen Rider with L after dinner.

Yesterday I mentioned I'd won an ebay auction, but I didn't mention what I'd bought. It was an 80mm/5.6 EL Nikkor enlarging lens. So this afternoon I looked for the parts that I'd need to make it work.

Checking Wikipedia showed that the lens has an M39 thread. Doing some googling, I found this page: Focusing helicoid, which almost gives a complete setup for what is needed to use the lens. The only thing that was missing is the best helicoid size for use with the 80mm lens.

The author does state on that page (regarding a 19 to 32 mm helicoid):

I can focus the above lens to infinity with a small margin left, and an 80 mm f/5.6 (both old and N type) with the helicoid almost totally extended.

So, what you could do is to use extension tube(s) plus 17-31mm helicoid (£30 on ebay). That should enable infinity to close-up focus. The other common helicoid sizes on ebay are 25-50mm (£47) and 35-90mm (£52). If the 80mm lens focuses to infinity with a completely extended 19-32mm helicoid, then that would mean that a helicoid that starts at 35mm would be too long for infinity focus. So it is probably a toss-up between the 17-31mm and the 25-50mm helicoids if I want infinity focus available.

Another article I read was The enlarging lens macro rig, which shows using the EL Nikkor lens reversed for macro work. Again, the parts mentioned are available on eBay.

I think what I will do is to wait until the lens arrives, and try holding / extending it manually. Then decide on what equipment to buy. I don't have any way to mount it to the camera at all at the moment.

The other equipment I need to use the lens for its intended purpose (UV photography) is a Vivitar 285 flash and a Baader U filter.

After writing this blog post so far, I realised that the old version of the EL-Nikkor 80mm/5.6 actually has a filter thread size of 34.5mm, not 39mm. So I spent most of the afternoon trying to find where you can obtain a thread adapter from 34.5mm to some normal size.

Some of the info I found said that you need to use a Series VI filter adapter. After much searching I did find an eBay seller that might sell a Series VI filter adapter with a 34.5mm thread. The filter adapter is the Ednalite 661. But, then you still need some way to adapt from a Series VI thread to a standard thread.

There didn't seem to be any Series VI to standard thread adapters on ebay. Just adapters of various threads to Series VI. I did find some info that suggested Series VI was a 44mm thread size. But then, there weren't any 44mm thread adapters on ebay either.

I then found this forum thread: Slide Dupes w/ D200, where one of the posters writes that the company BORG makes a 34.5mm to M42 adapter, with part no. #7848. Googling for that brings up this pdf: BORG parts catalog, where you can see an image of the adapter and a fuller description:

M42P1 to M34.5 AD
Connects a reversed Nikkor EL 50/4 lens to focusers. (A reversed EL enlarger lens can be used as a high-resolution macro lens.)

This adaptor has male threads on both sides to enable reversing the lens. It is not really a filter thread adapter. You would have to get a M48 to M42 step down ring, mount it on the front of the Baader U filter (possibly with filter adapter), and then reverse mount it to the BORG 7848. I'm not sure if the filter being reverse mounted would make any difference.

I did find on ebay an M42 female to M42 female T thread adapter. In theory this should work, but the part looked a bit thick to me.

The other possible solution could be if the filter could be mounted behind the lens. At the moment I am not entirely sure what size thread the Baader filter uses on both sides. On the Baader website they sell a range of adapter rings. But they also say adapt our Astro 2 "eyepiece-filter (M48), indicating that the filter thread of the filter itself is M48. In which case I would have thought a standard 48mm - whatever size adapter should be okay.

Doing some more research, I found this page with quite a bit of useful info on creating a setup for UV photography: Kevin Collins: The equipment I use for ultraviolet photography. And here is a link to the same images on flickr: kevincollins123 > Collections > Exotic Spectra > Reflected Ultraviolet.

Next I looked at the flash. The Vivtar UV Flash conversion page I had looked at before suggested the 285HV, 285, or 283 flashes. I wondered what the difference was. It seems that the 285 has a zoom head, while the 285HV is more likely to have a trigger voltage that won't fry your camera, but there were also some new models produced that are very low quality and break easily. The 283 is a more basic flash.

Looking at them on ebay, there isn't a way to manually control the flash power. They feature an auto thyristor for determining the flash power. This can be removed and replaced with the Vivitar VP-1 Vari-power module. But this costs about £30, and only seemed to be on ebay from US based sellers.

Then I managed to find a couple of resources that show you can just use a 100k potentiometer (about £2 inc. P&P on ebay) instead of the VP-1: Vivitar 283 DIY varipower and HiViz Electronic Guidebook for High-Speed Flash Photography: Activity 2. Controlling flash duration.

Researching this various stuff took me most of the afternoon and evening.

In the evening I also wrote up a recipe I made a while back and made some left-over cereal and biscuit cake.

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