Well, I couldn't use the TTL light meter because it didn't work at all.

But today, when I came back NYC after I shot portrait with model, I pushed to 'ON' and it worked. I was at outside with half cloudy and half sunny day and the temperature was around 37 degree.

I checked if I can use the meter in my home but it didn't work again.

I'm wondering that the TTL light meter require some conditions to use or not.


Is there any conditions or requirements to use the TTL light meter?

[desertscape]

You need to clean the spring loaded pins on the bottom of the prism and the contacts at the back of the screen to be sure that is not the problem. Sometimes shooters get faked out by the metering range of the TTL, thinking that it does not work, only to find that they are trying to use it beyond its capabilities. As an example-- you have the ASA set to 800 and shutter speed of 1/4 sec but the meter does not register anything. That is because what you are trying to meter is beyond its metering range. Pentax has a booklet explaining all this for the TTL.

The TTL does well in cold weather and 37 degree F is not a problem. The bodies sometimes have problems at less than 30 degrees.

You need to clean the spring loaded pins on the bottom of the prism and the contacts at the back of the screen to be sure that is not the problem. Sometimes shooters get faked out by the metering range of the TTL, thinking that it does not work, only to find that they are trying to use it beyond its capabilities. As an example-- you have the ASA set to 800 and shutter speed of 1/4 sec but the meter does not register anything. That is because what you are trying to meter is beyond its metering range. Pentax has a booklet explaining all this for the TTL.

The TTL does well in cold weather and 37 degree F is not a problem. The bodies sometimes have problems at less than 30 degrees.

Cool got it

[odinkos]

Just in case it's a more serious issue I found this site the other day: Daren Sefcik: Pentax 6x7 TTL Prism Repair and Exposure Meter Adjustment
If you're feeling frisky, it might be what's wrong with you meter. Good luck either way!

[gofour3]

Your other option is to ditch the TTL prism and get a good handheld light meter.

My 67 TTL metered prism was also acting funny and I just gave up on it. I now use either a Pentax V Spotmeter or Gossen Luna Pro SBC instead.

Note the 67ii AE metered prism is a totally different beast and it IS reliable.

Phil.

[iCrop]

Your other option is to ditch the TTL prism and get a good handheld light meter.

My 67 TTL metered prism was also acting funny and I just gave up on it. I now use either a Pentax V Spotmeter or Gossen Luna Pro SBC instead.

Note the 67ii AE metered prism is a totally different beast and it IS reliable.

Phil.

Yet another option, I ended up getting the Folding Focusing Hood and use another camera (usually the K-3) as a light meter. Works pretty well.