Filter thread size for Kodak Ektar 203mm f7.7

lharby

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I apologise in advance for a very dry thread but I really hope someone can help me with this.

Not long ago I bought a Graflex Crown Graphic Special. It is mounted with a Kodak Ektar 203mm f7.7 lens.

My goal is to add diopters/close up lenses either directly onto the existing lens or via stepper adapters (as I have a good set of diopters which are 67mm)

I have tried various threads in order to track this information down, namely:

1 - https://www.largeformatphotography.info/forum/showthread.php?69315-Filter-size-for-threaded-Ektar-203mm-lens

2 - https://www.largeformatphotography.info/forum/showthread.php?100145-Ektar-203-filter-thread-size

The advice varies and seems to imply that the lens in the UK might differ from a US version (plus I don't know which mine is). Also that this lens takes push on filters and that the thread size is metric. Although I cannot verify this.

My stepper adapters start at 37mm. I bought a 35mm > 37mm as well as 35.5mm > 37mm. Neither of these fit the Ektar lens (both are larger)

Stepper rings.jpg

So then I bought a Kodak Close up lens (I was sure this said size 370 which is on the lens but actually rechecking it says size 320). This does not fit.

Kodak Close up lens 1.jpg

Then I purchased Series V - VII adapters. These also do not fit.

Kodak Series V-VII adapters.jpg

Luckily none of this has cost me much, but it is frustrating.

Does anyone know the actual thing I need? I guess Kodak close up lens Size 370 would be the next thing to try. But I would still prefer to do this with a stepper.

The lens clearly has a thread on the inside, so this information about push on filters seems not to apply here. Any help greatly appreciated.

Kodak Ektar lens 1.jpg
Kodak Ektar lens 2.jpg
 
Last edited:

mpirie

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I just took a vernier to my 203mm f7.7

The diameter of the inside thread looks to be about 31.2mm, but the exposed thread is for the front securing ring holding the elements in. There may not be enough thread visible to use a filter thread.

Mike
 

Keith Haithwaite

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I just took a vernier to my 203mm f7.7

The diameter of the inside thread looks to be about 31.2mm, but the exposed thread is for the front securing ring holding the elements in. There may not be enough thread visible to use a filter thread.

Mike
I just did the same with my 203mm f7.7 Mount 370 and I agree with Mike on all counts, I don't think that the tiny amout of exposed thread was ever meant to take a filter - it also looks a much finer thread than filters use.
 

Alan Clark

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I have a Kodak 203mm lens, along with some Kodak colour filters, size no. 370, and a Kodak Lens Attachment size no. 370.
The Lens Attachment is a push fit onto the lens (which has an outside diameter of 37mm.) and acts as a filter holder. To fix a filter in place you unscrew the front part of the lens attachment, put the filter in- in your case a close-up filter- then screw the front of the lens attachment back in place. There is no screw thread on the filter. It has an outside diameter of 41mm, and is a snug fit in the Lens Attachment.
So to solve your problem you need a Kodak Lens Attachment size no. 370 37.0mm and some close-up lenses with an outside diameter of 41mm. Good luck.

Alan
 

lharby

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I was about to write phooey in relation to the first two responses. But thank you Alan. Much appreciated.
 

Alan Clark

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There's another solution to your problem. You could mount the close-up lens BEHIND the Kodak lens by attaching it to the back of the lens board. This is actually what I do with my yellow, orange & other contrast filters, despite having the lens attachment mentioned above. This is because I like to use modern multi-coated filters, and have a set in 49mm thread size for my OM1 camera. As you will know these modern filters have a metal rim with an inside AND an outside thread. So they screw into each other. I simply removed the glass from an unwanted 49mm UV filter, and glued its metal rim onto the back of the lens board, surrounding the Kodak lens locking ring. So when I want to use a filter I simply screw it in place behind the lens. I'm thinking you could use the same arrangement, but with a close-up lens, and also with colour filters if you use them. The thread size doesn't have to be 49mm, but should be big enough so the metal filter rim is bigger than the lens locking ring.

Alan
 

thronobulax

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ISTR that Kodak made so-called "Series" adapters for these lenses but my ancient memory is blurry on the detail.
 

Ian Grant

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UK made 203mm f7,7 Ektarts differ from their US conterpart. The Mount 370 was unique to Kodak Ltd, like Alan I have some odd filters that fit but not ones I'd use. Here in the UK while the 203mm f7.7 Ektar was available seperately from Kodak most were sold with the Half Plate Kodak Spcialis 2 cameras, they cover 7x5 with some for movements. They are excellent from Infinity to 1:1.

Very sharp lenses but the downside is the earliest are an Epsilon and lter ones in aProntor SVS shutter which has no preview lever and no T setting so requires a locking cable release for focussing, a few very late ones were in a Compur Rapid but these are rare. Unlike the US version these British made 203mm Etars fit a Compur/Copal/Prontor/Epsilon.Seiko #0 shutter. Very late US versions were in a Graphic Compur #1 shutter, after Kodak/Wollensak ceased shutter manufacture

Best solution would be to find a push on filter and try ot fitor glue an adapter to it. Just to add to the confusion though, the boxed Size No 370 lens hood I have is a srew in one, roughly 43mm so too large for the 203mm Ektar, the size 370 is engraved on it, However th push on Poatra No 1 close up lens is Size no 370, 37.0mm and fits my British 203mm Ektars and 100mm f4.5 Kodak Anastigmat.

Unscrewing the Porta filter the lens hood fits. Looking on Ebay 370 filters are available but you need a filter holer that unscrews, 370 filters were actualy 41mm and could be bought seperately. I do have some Kodak Professional and also Dealer catalogues I'll scan anything relevant tomorrow.

Ian
 

thronobulax

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I would also mention that I never mount filters on my LF gear. I just just filter gels in frames and hold them in front of the lens during exposure.
 

lharby

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thronobulax thank you. I did get the Series V - VII adapters, but these do not fit my lens (pictured above). Also I don't know if diopters working unless they are fairly well secured, but I can look into it. It would make it difficult with bellows extended whilst trying to look through the ground glass.

Ian Grant, thank you this is excellent. Is this the right thing?

It says 41mm on the outside, which is what Alan Clark mentions above.
 

thronobulax

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thronobulax thank you. I did get the Series V - VII adapters, but these do not fit my lens (pictured above). Also I don't know if diopters working unless they are fairly well secured, but I can look into it. It would make it difficult with bellows extended whilst trying to look through the ground glass.
Ah yes, I'd forgotten you were using diopters.

Assuming this is as essential to your work as the discussion suggests, another possible path would be to have a machinist make something for you. A single piece - while expensive - might not be cost prohibitive in the scheme of things.
 

Ian Grant

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Ian Grant, thank you this is excellent. Is this the right thing?

It says 41mm on the outside, which is what Alan Clark mentions above.
That's a filter that fits the Mount 370 filter holder, you need the holder.

I have two sets of adapters like you show in th opening post but couldn't find them last night, The M370 threads will be Imperial so matching to metric might be difficult.

Ian
 

Alan Clark

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What Ian is calling the Mount 370 filter holder is actually called the Kodak Lens Attachment, as I said in an earlier post. Mine is in its original box; and that's what it says on the box.

Alan
 

Ian Grant

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1631270064447.png
From a Kodak Ltd Professional Catalogue, no date but approx 1960, in the days when Kodak Ltd still had 10 wholesale stores for professional photographers in the UK and Ireland.

Alan's right about the basic Mount 370 Lens attachment and retaining ring, but Kodak also sold some filters like my Portra No 1 in the 370 mount, that means there's more options.

Ian
 
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