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Mamiya 300/2.8 - filters (#87 IR)

G

gerald.d

Well-known member
Ok, so I appreciate that this is maybe just a little too much of a niche question, but I know we have a huge amount of experience on this here forum, so I thought I'd put it out there just on the off-chance...

I want to get an #87 Infrared filter for my Mamiya 300mm f/2.8. This lens has a drop-in filter at the back, and comes with a set of glass filters, and a holder for gelatin.

The glass filters screw into the filter holder - quite amazing actually that they provide holders for every filter that ships with the lens, so you'd never actually have to unscrew them, unless that is you wanted to use an alternative.

I've measured the thread on one of these glass filters, and it was 45.9mm.

Now it turns out that Heliopan make 46mm glass IR filters -

Infrared #87 | B&H Photo Video

Does anyone know whether, or have experience of, 46mm screw in Heliopan filters fitting the Mamiya filter holder?

Obviously I could go the easy route and just get a gelatin filter cut down to the required 43.5mm size for the gelatin filter holder, but I'd prefer to go glass if at all possible.

Thanks in advance, and kind regards!

Gerald.
 
Don Libby

Don Libby

Well-known member
Gerald, from the limited knowledge I have in IR you are much better off using glass over gelatin as glass has a "cleaner" way of shooting IR. That said why not try a step ring?
 
Don Libby

Don Libby

Well-known member
Just did a very fast search for step up rings and could find none listed at 45.9. I'd suggest ordering the 46 and seeing if it wouldn't actually fit.
 
H

hsteeves

Member
I am willing to bet that if you checked the specs on that lens, that it says it takes 46mm filters. The only problem is that some of those lenses take a unique thread - even if it is a common size. Best thing is to take your holder to someplace that has filters and see if a 46 fits. Take care not to cross thread or fit a fine thread to a course thread.
 
G

gerald.d

Well-known member
Thanks guys - the only specs available from Mamiya are that the gelatin needs to be cut to 43.5mm. They don't mention the glass filter thread size at all - http://www.mamiya.co.jp/home/camera/eng/products/645protl/lenses.html#y02380

One downside of living here (Dubai) is that it's extremely unlikely that I'll be able to find somewhere with a 46mm filter (of any sort) in stock.

I'll probably take a punt on the Heliopan and cross my fingers!

(Step ring isn't an option Don - not sure if I made it clear, but this is a rear drop-in filter - there'd be no space for a step ring to fit)
 
J

John_McMaster

Active member
Taken a look, my gel filter holder has a ring which screws out and leaves a glass layer in. This ring fits outside E46 filters (Leica filter fitted tightest of various I tried). Due to the thickness of the E46 you would have to unscrew the glass part as well but I didn't try ;-)

With the glass out I think an E46 filter could be fitted into the gap (would need some sort of fixing) and be inserted into the lens, although I have not looked to see if narrower inside lens that the top is.....

One issue is no IR marks on lens, I know how hard it was to get things in focus at wide apertures with a 35mm/IR720 on my M8!

john
 
G

gerald.d

Well-known member
Chiaroscuro_NZ said:
Taken a look, my gel filter holder has a ring which screws out and leaves a glass layer in. This ring fits outside E46 filters (Leica filter fitted tightest of various I tried). Due to the thickness of the E46 you would have to unscrew the glass part as well but I didn't try ;-)

With the glass out I think an E46 filter could be fitted into the gap (would need some sort of fixing) and be inserted into the lens, although I have not looked to see if narrower inside lens that the top is.....

One issue is no IR marks on lens, I know how hard it was to get things in focus at wide apertures with a 35mm/IR720 on my M8!

john
Click to expand...
Thanks John - if you have a look at the "normal" filters (not the gelatin one), you'll notice that you can actually unscrew the entire glass filter leaving just the drop-in frame. This is where I'm hoping a 46mm filter might work.
 
J

John_McMaster

Active member
Have you unscrewed one of yours? It is an inner circlip ;-) The remaining frame is too small for an E46, you would need to take out all the threaded part...

john
 
G

gerald.d

Well-known member
Chiaroscuro_NZ said:
Have you unscrewed one of yours? It is an inner circlip ;-) The remaining frame is too small for an E46, you would need to take out all the threaded part...

john
Click to expand...
The entire filter unscrews -



I can only do this on a couple of my filters - I think maybe the others have had their thread ruined!
 
G

gerald.d

Well-known member
OK, so the 46mm Heliopan arrived.

The filter screws into the drop-in holder for the Mamiya, but the depth of the filter means that you can no longer fit the drop-in filter into the slot on the lens, so....

The Heliopan can be disassembled - the filter holder is actually two pieces that unscrew, so the glass comes out. The glass is an exact match for the size of the glass in the Mamiya filters, so all you need to do is remove the metal spring that keeps these in, take out an existing filter, and replace with the IR filter. Job done!

Whether or not this is of any interest to anyone other than me is of course another question entirely :D
 
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