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05-18-2012, 03:03 PM   #1
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P30 & P30N - really limited to ISO 1600?

I bought a roll of Ilford Delta 3200 film and thought that of all my film cameras (SP1000, MX, P30, P30N, KX) that I would only be able to use it in the KX, as it's the only one that can be set to that film speed. Of course, I could use another and remember to alter the settings as necessary for the correct exposure, but it would be a pain.

The P30 & P30N use DX-coding to detect the film speed, and if they don't detect it they go automatically to ISO 100. I've checked the manual for the P30T (didn't find the others) and it states what is also stated in the camera database here - that these models are limited to ISO 1600. They do have all six sets of contacts to detect the coding (I've read that some cameras can only read the most common film speeds because they lack some of the contacts).

However, I did a quick check with both just now. I left them empty (therefore defaulting to ISO100) and metered two scenes with the same lens, same aperture. One showed a 2 second exposure would be needed and the other a 4 second exposure (it's night time). Then I loaded the Ilford (without actually loading it, just so that the camera detected it) and metered the same scenes. They showed 1/60s & 1/125s respectively, a difference of five stops, the same as between an ISO 100 film and an ISO 3200 film.

So, they both appear to be able to detect the 3200 film and meter correctly. Am I missing something? Why do the manuals state that they are limited to 1600? Has anyone successfully used a 3200 film in a P30?

05-18-2012, 04:01 PM   #2
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Hi Jonathan,

I can't remember the pattern for the DX coding, but if a camera was missing a contact (or it wasn't wired up), it would probably default to the highest ISO available with the contacts it had (could be either 800 or 1600 I think?). Only if there was no DX coding would it default to 100.

Also, Delta 3200 has a base ISO value of 800 from memory, to get 3200 you have to extend development (at which point it is EI - Exposure Index rather than ISO). If the camera recognises ISO 1600 you could shoot it at that and compensate by extending development less than 3200. When getting it processed commercially, you should indicate the EI value so the lab know how to develop it.

Last edited by johnha; 05-18-2012 at 04:06 PM.
05-19-2012, 12:35 AM   #3
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QuoteOriginally posted by johnha Quote
Hi Jonathan,

I can't remember the pattern for the DX coding, but if a camera was missing a contact (or it wasn't wired up), it would probably default to the highest ISO available with the contacts it had (could be either 800 or 1600 I think?). Only if there was no DX coding would it default to 100.

Also, Delta 3200 has a base ISO value of 800 from memory, to get 3200 you have to extend development (at which point it is EI - Exposure Index rather than ISO). If the camera recognises ISO 1600 you could shoot it at that and compensate by extending development less than 3200. When getting it processed commercially, you should indicate the EI value so the lab know how to develop it.
You're right. This is from Ilford's data sheet:

DELTA 3200 Professional has an ISO speed rating of ISO 1000/31 (1000ASA, 31DIN) to daylight. The ISO speed rating was measured using ILFORD ID-11 developer at 20C/68F with intermittent agitation in a spiral tank.

But so is this:

The recommended meter setting for DELTA 3200 Professional is EI 3200/36, but good image quality can also be obtained at meter settings from EI 400/27 to EI 6400/39. It can be used in all types of lighting.

But according to the diagram here DX encoding - Wikipedia, the free encyclopedia the dx coding on the film cassette is "custom 2". What does that mean? Would I need a camera that has pre-programmed custom values, presumably designed to allow pushing and pulling? Why then do the P30s appear to correctly register the film as 3200?

Last edited by Jonathan Mac; 05-19-2012 at 12:43 AM.
05-19-2012, 09:42 AM   #4
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The camera may have the contacts to support higher than ISO 1600, but meter support is another matter. If the manual says 1600, it means 1600.


Steve

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