Exposure compensation and TTL flash.

[redstarjedi]

I have a fantastic contax RX. There is one problem, a repair man explained that the meter consistently over exposes by two thirds of a stop. I have two options, set the exposure compensation dial back two thirds of one stop, or set a higher iso by two thirds of a stop. For natural light photography the results have been great, both in c-41 and black and white.

Last night i set my contax TLA 200 flash on top of my RX. I was shooting tri-x @ 1600. So i set the iso to 2500 which is two thirds of a stop above 1600. The flash output was VERY VERY weak. My flash is in working order. Allegedly the TLA 200 (contax G1 and G2 flash) is TTL with any contax body. However when i look at the flash shoe on the tla 200 i only see two metal points. On my TLA 360 i see 5.

I am wondering if the contax tla 200 was fooled by the 2500 iso, because it may not be a true TTL flash. It may have simply determined the flash output by the ISO setting.

Either way, i'll develop the roll tomorrow and post the results. Until then if any one could answer the question: "does compensating for a over exposing meter ruin the ttl flash readings?"

Thanks.

 

[cowanw]

Yes it would be fooled because you are fooling the camera, which is not functioning up to par. Set your camera manually with the fudged settings as per your routine (being sure to pay attention to the maximumshutter speed setting) and then shoot with the ASA at 1600 for the flash.

 

[markbarendt]

"does compensating for a over exposing meter ruin the ttl flash readings?"

Thanks.

No, it shouldn't.

 

[swchris]

If you meter overexposes by 2/3 stops, and you want to shoot at 1600, you shoud set the meter to 1000, not 2500.

Edit: Oops, sorry, I got it the wrong way. You were correct at 2500.

 

[benjiboy]

Why do you need flash when using 1600 I.S.O. film ?

 

[markbarendt]

Why do you need flash when using 1600 I.S.O. film ?

That's a good question

Actually i see plenty of possible reasons.

It may be really dark.

May want to shoot at f/8.

A little fill on the dark side.

One of the biggies for me is simply to change the placement of the main subject in relation to the background.

 

[redstarjedi]

I have a fantastic contax RX. There is one problem, a repair man explained that the meter consistently over exposes by two thirds of a stop. I have two options, set the exposure compensation dial back two thirds of one stop, or set a higher iso by two thirds of a stop. For natural light photography the results have been great, both in c-41 and black and white.

Last night i set my contax TLA 200 flash on top of my RX. I was shooting tri-x @ 1600. So i set the iso to 2500 which is two thirds of a stop above 1600. The flash output was VERY VERY weak. My flash is in working order. Allegedly the TLA 200 (contax G1 and G2 flash) is TTL with any contax body. However when i look at the flash shoe on the tla 200 i only see two metal points. On my TLA 360 i see 5.

I am wondering if the contax tla 200 was fooled by the 2500 iso, because it may not be a true TTL flash. It may have simply determined the flash output by the ISO setting.

Either way, i'll develop the roll tomorrow and post the results. Until then if any one could answer the question: "does compensating for a over exposing meter ruin the ttl flash readings?"

Thanks.

In terms of flash output the contax tla 360 was WORSE! than the TLA 200. There is a exposure comp menu on the TLA 360, but it didn't change any thing. If i switch the TLA 360 from TTL to Auto it fires much brighter. I've used the TLA 360 in Auto on a SRT 202 very well. If i keep it in TTL but i lower the ISO it flashes fine. Somehow i think the TLA 360 has a set flash output after a certain ISO. I also have a TLA 280, and that seems to flash just fine at any ISO.

And yes, i know that flash output is going to be weak at high ISO's however the output was sooooo weak that my wife didn't think the flash was on when i took a photo of her.

Edit: well it seems that in TTL mode the flash only goes from 25 to 400 iso. Where as in Auto mode it goes from 6 to 6400 iso.

Sadly i can't change the ISO on the 360 flash once its connected to the RX. It always goes to what ever the iso in the camera is.