Looking for reciprocity data for Svema MZ3/Foqus A125

[StrangleMeRandy]

Howdy, I have two films I'm hoping someone has some experience with for long(ish) exposures. The MZ3 is an old film duplicating (forget the proper term) stock that is currently made by Astrum, and the A125 is a near total mystery, currently made by some guy in Russia, with some comparing it to military aero-reconnaissance film. I managed to get the datasheet for the MZ3 from the very helpful customer support, but it doesn't have reciprocity data and they couldn't help me. The A125 is a near total mystery, as the store that sells it could only give me some development info, and I don't know enough Russian to search Russian forums myself.

In case you were wondering, yes, the number in each name is the ISO. I don't see myself doing longer than maybe a second with the A125, and I plan to bracket sensibly when I shoot slower than, I dunno, half a second. With the MZ3, however, doing long exposures was the whole point of getting such a slow stock, and I'd hate to go in blind, bracketing five or more stops, especially when each exposure takes several minutes! I am prepared to, of course, I'm just hoping someone here has played with it a fair bit and can point me in the right direction. I've done a little bit of long exposure stuff with Tri-X, doing nighttime exposures on the order of 15 seconds to a minute, though I just finished that roll and don't have the results yet.

 

[removedacct1]

I've used the MZ3 a fair bit, and I know nothing about its actual reciprocity characteristics. So, my approach has been to start at the 3ASA metering value (usually 3-15 seconds depending on circumstance and f-stop) and then I bracket half stops MORE (not bothering with less than meter), and what I find is that by the time I have tripled the starting exposure duration, I am well into serious overexposure. In general now, I tend not to bracket more than two frames past meter value: 1/2 stop more, and 1 stop more. It seems to have less reciprocity than I expected it to, but again, I have no clue what the actual reciprocity is.
I hope that is at least somewhat helpful.

A recent photo made on MZ3 with a Kodak Retina #126 with a Tessar lens. Exposure was 25 seconds at f16 under heavy clouds: https://farm8.staticflickr.com/7856/33165154778_259d6ce8c6_h.jpg

 

[StrangleMeRandy]

...I bracket half stops MORE (not bothering with less than meter), and what I find is that by the time I have tripled the starting exposure duration, I am well into serious overexposure. In general now, I tend not to bracket more than two frames past meter value: 1/2 stop more, and 1 stop more. It seems to have less reciprocity than I expected it to, but again, I have no clue what the actual reciprocity is.
I hope that is at least somewhat helpful.

A recent photo made on MZ3 with a Kodak Retina #126 with a Tessar lens. Exposure was 25 seconds at f16 under heavy clouds: https://farm8.staticflickr.com/7856/33165154778_259d6ce8c6_h.jpg

This is extremely helpful, thank you! I wasn't planning on bracketing for less of course, and it's good to know that, at least under a minute, it doesn't underexpose horribly. That's a lovely picture, you wouldn't happen to recall what bracket it was, would you? And do you have any minute-plus examples?

 

[Ko.Fe.]

Not sure why you are dealing with films like these...

This page has developing info for a125. In Russian.
https://rangefinder.ru/club/viewtopic.php?f=10&t=16702&start=1860

D76 1:1 20С 16 min
D76 1:3 20С 18 min
Pirocat 1:1:100 20С 18 min
Rodinal 1:50 20С 12 min
Microfen 1:1 20С 13 min
Ilfosol3 1:14 20С 7.30 min
Microl stock 19С 12 min


Svema doesn't makes any films. Astrum, either, they could pack anything available for resale.

 

[StrangleMeRandy]

Not sure why you are dealing with films like these...

I've tried every other black and white stock and didn't like any of them

Thank you for the dev info and forum link! I actually know a little bit of Russian and can read about as well as a four year old, I just don't know where to begin with searching Russian forums. Between online slang and photography terms more arcane than фото I'm totally lost lol

 

[removedacct1]

Not sure why you are dealing with films like these...

Svema doesn't makes any films. Astrum, either, they could pack anything available for resale.

Why does he want to “deal with these films”? Because they are unique compared to what everyone else has to offer, is why. Did you look at the photo I linked to? That’s from a 35mm MZ3 negative taken with an 80 year old uncoated lens. This film makes 35mm almost emulate 4x5!

And I wouldn’t be so sure about Astrum not making their own films. I’ve bought Astrum Foto 100, 200 and 400 from Dmitriy directly. True, Svema doesn’t make film anymore, and that’s because they’ve been defunct since 2000, at which point Astrum acquired some of their facility and resumed manufacture of several of their films under the Astrum name. The Astrum films are surprisingly good (something to consider if you are a fan of “old school” emulsion types: Astrum Foto 200 reminds me of Plus-X) and I’m enjoying them a lot. Including shipping costs, the Astrum films cost about $3.50 per 36 exposure roll, which makes them an attractive option.

Astrum Foto 200, shot at 125 ASA, processed in Rodinal 1:50
https://farm2.staticflickr.com/1820/43839925482_d6314ab4a3_k.jpg

 

[Ko.Fe.]

Why does he want to “deal with these films”? Because they are unique compared to what everyone else has to offer, is why. Did you look at the photo I linked to? That’s from a 35mm MZ3 negative taken with an 80 year old uncoated lens. This film makes 35mm almost emulate 4x5!

And I wouldn’t be so sure about Astrum not making their own films. I’ve bought Astrum Foto 100, 200 and 400 from Dmitriy directly. True, Svema doesn’t make film anymore, and that’s because they’ve been defunct since 2000, at which point Astrum acquired some of their facility and resumed manufacture of several of their films under the Astrum name. The Astrum films are surprisingly good (something to consider if you are a fan of “old school” emulsion types: Astrum Foto 200 reminds me of Plus-X) and I’m enjoying them a lot. Including shipping costs, the Astrum films cost about $3.50 per 36 exposure roll, which makes them an attractive option.

Astrum Foto 200, shot at 125 ASA, processed in Rodinal 1:50
https://farm2.staticflickr.com/1820/43839925482_d6314ab4a3_k.jpg

Unique emulsion talks are somewhat important if negative is scanned. If printed under enlarger, it was proved on back then APUG to have no significant factor on the print.

 

[removedacct1]

Unique emulsion talks are somewhat important if negative is scanned. If printed under enlarger, it was proved on back then APUG to have no significant factor on the print.

So, being able to make an 11 x 14 print that shows no grain from a 35mm negative is “no significant factor”??

 

[Ko.Fe.]

So, being able to make an 11 x 14 print that shows no grain from a 35mm negative is “no significant factor”??

Of course it is not. Why someone like you is so anal about absence of grain is behind me. Film is the grain.
If I need no grain I use digital.

 

[removedacct1]

Of course it is not. Why someone like you is so anal about absence of grain is behind me. Film is the grain.
If I need no grain I use digital.

Here we go again - a rudely opinionated photographer telling other people what should and should not be important to them. Telling others what they are allowed to put in their personal toolkit is totally obnoxious. This sh*t is what makes forums like this an unpleasant place to seek information.

 

[StrangleMeRandy]

Alright, simmer down fellas. I literally just joined Photrio, I don't want to immediately start a ruckus. Paul, don't let the other guy get to you, plenty of people with crazy opinions. I agree that there's far more to film than grain, and sure, digital can emulate plenty of that, but not all of it. KoFe, I generally get my film scanned, so as per your reference (I'd like to see that if you can find it!) using unusual film stock will have a relevant impact.