DX coding weirdness

jrong · 05-22-2006

I have an unusual problem here. I have been on holiday, and have been shooting with my Contax G2 and rolls of Fuji Neopan 100 film. One afternoon, I stuck in a roll of APX 100 film and shot with my 21mm lens and viewfinder, and did not peer through the actual camera viewfinder until most of the roll was used up.

When I did look through the viewfinder though, I noticed that the metering was funky... it was showing a shutter speed of 1/6000 for a bright sunny scene at f4 or so. I was shocked at this. I checked the top of the camera display and it read "DX" as it has always done - but when I checked the ISO setting by pressing the ISO button, it read "2500", whereas it should only have been 100!

I guess I should really have checked, but I'd always trusted my cameras to read the DX properly.... and a further snag was that I was using my 21mm viewfinder and not the camera viewfinder so I did not notice any odd metering readings until it was too late.

So I took out the APX film and put in a fresh roll of Neopan 100. The DX reading was correct this time, at a 100.

I'm stumped - the batteries are fresh-ish, I replaced them about 4-5 rolls of film ago, a few months back. Has anyone experienced similar weirdness with their G2 cameras?

Any way I can realistically salvage a roll of ISO 100 film shot at ISO 2500?? (It is Agfa APX 100... not sure how much it can be pushed without resulting in golfball grain).

kaiyen · 05-22-2006

is it possible that there was some dirt or something either on the film canister or on the contacts in your...contax?

also, perhaps the coding was tarnished or damaged on the film canister. that happens if you've had it rolling around outside of its plastic case thingy.

I am not articulate today.

allan

jrong · 05-22-2006

The film was fresh from a canister, so no there was no dirt, nor any scratches. I had a look at the DX coding for ISO 100 and 2500, and for the camera to have made this mistake, it should've detected 2 contacts where there weren't any. This is odd because you'd think that the opposite was a more likely thing to have happened.

Does the camera check the DX coding on the canister every time you turn the camera on, or only once when you load the film?

Socke · 05-22-2006

Hm, I think the DX contacts are nothing more than electrical switches which are eiter open or closed. So every time the camera is switched there is electricity on the closed contacts an non at the open ones.

ClaremontPhoto · 05-22-2006

Tell the lab what happened. You are not the first. See what they can salvage,

jrong · 05-22-2006

I develop my own film. Was just wondering whether I should develop for 2500 (and hope for the best) or develop normally and assume that the camera's DX setting went haywire only towards the end of the roll, so most frames can be salvaged. It's a bit of a gamble....

Che Hale · 05-24-2006

You could do a test strip from the beginning. It would tell you if it messed up mid roll or at the beginning.

Che.