It Says "400 ISO" On The Box

Hi All,

I've been shooting APX 400 at box speed but the general impression I get is that this film is not a true 400 speed film. Anyone have experience shooting with APX 400 and what speed do you rate this at? I'm thinking 250 to 320 EI.

In case it matters, the developers I use consists of Rodinal, FX-37 and a pyro-metol TEA developer.

The reality is that ALL film exhibits different effective ISO's when developed by different people with different developers, and different water supplies (used in mixing developers) worldwide. In the lab, under specific controlled conditions with a specific developer, with specific agitation, films are rated for ISO. Most people get more satisfactory results with b/w films by rating them a bit lower than box ISO.

I used to use this with an EI of 200 developed in either D-76 1:1 or HC110 b.
It definitely is underexposed at 400 with any "regular" developer.

A film is ISO when it is shot and processed in ISO condition, that's it.

If you have better results with a different EI in non-ISO condition, I don't think you have a case for Consumer Report...

hi there

i am probably speaking like the fool
but the iso the film is rated has no
relation to how one should set the iso
in one's camera. like developing times
and all that jazz it is just a starting point.
(if you do that sort of thing yourself)

i have to admit though when i am sending color
film or e6 film to the lab - everything comes back
nice-nice when i use the recommended film speed / box speed.

maybe it is just a conspiracy?

john

Colour films involve tightly controlled processing, therefore there is only a really limited number of actual variations on processing, which explain the successful results coming out of shooting at box speed.

On the other hand, with B&W you can get usable images through so many different means, that it is why we must understand that ISO ratings are meaningful and accurate only in an ISO situation.

We all know that using a given developer allows us to shoot at EI #1 and using another developer requires us to shoot at EI #2. There is no trickery here. If you cook a leg of lamb at 225F you can do so in seven hours, but if you cook it at 350F you should be OK at 2h max.

The standard for ISO film speed involves a particular developer, processing sequence, and measurements. The point is not to have something that is perfectly representative of the average consumer experience, but to have something that is controllable in production circumstances, batch-to-batch consistency among other things.

If you want to verify the true ISO speed of a film, get a copy of the ISO standard, and do the testing accordingly. Otherwise you're just reflecting the bias of your experimental circumstances.

Snapshot, none of the developers you are using are part of the ISO standard. Why would you expect your results to match precisely this standard?

Others have already commented on the "true ISO' factor...

However, I've always shot it at 400 in my folders. I have developed it in Rodinal 1+100 and got very nice results.

I've also shot Rollei Retro 400 in 35mm (same as APX400) and rated that at 400 too, but this time developed in PC-TEA 1+50. Once again, nice negatives.

in our school situation the students may use 160 to 400. Each student test for specific EI and as you can see it varies.

With my 35mm nikons, one i rate the film at 160 the other 250.

with roll film 200, sheet film 160, and this is all ilford hp5+, so as others have suggested the speed will vary with a variety of situations.

Everyone is confirming what I'm seeing with APX 400. Unfortunately, my metering skills were off due to years of relying on digital automation. As a result, I was getting inconclusive results. Just plain laziness on my part.

Snapshot said:

Hi All,

I've been shooting APX 400 at box speed but the general impression I get is that this film is not a true 400 speed film. Anyone have experience shooting with APX 400 and what speed do you rate this at? I'm thinking 250 to 320 EI.

In case it matters, the developers I use consists of Rodinal, FX-37 and a pyro-metol TEA developer.

Click to expand...

I just bought 50 rolls from Freestyle as my "shoot around film", after testing with my Sigma SA 9 I rate it at 320 for Edwal 12, 200 for Microdal X, and 400 for DK50. I would have thought that it would test out at 400 for Rodinal as well, but I am using up all of my old stock so I have not test with Rodinal.