KM 5D Owners

[KennyC]

Quiet forum, eh? Where's the Minolta users? Guess this IS my first post so I can't say much.

Well, I'm the proud new owner of my first DSLR, the KM 5D, and I'm loving it so far. I have, however, noticed something a little...odd, hence this post. While playing around with very long exposures at high ISO (3200) I noticed something strange, a purple spot in the upper left corner. So I did some more testing and it was definately a repeatable problem. Here are some examples, taken in dark rooms with the lens cap on:

1. 30sec, ISO 3200


2. 131sec, ISO 3200


3. 445sec, ISO 3200



The digital noise I certainly understand, but a purple spot? Thinking it may just be my camera, I went over to the local Wolf Camera and tried it on their display 5D...same result. Do you other 5D owners notice the same thing?

It probably isn't really a problem, since I'll really never need to do long exposures at ISO3200, but it is very interesting to me...

[JDArt]

Good to have you, Kenny. Go round up some more KM users, would you?

[Mr. Pickles]

So you get the purple when you shoot 3200 without the cap on? I'd say it has something to due with the camera, and is probably that way on all of them. Might be the sensor heating up

[KennyC]

Thanks JD, I'll try to rustle up some more.

Pickles - Yeah, it showed up during a normal exposure too, still 30sec at 3200 ISO though. Good point about the sensor heating up, I'll give it a try again sometime after a long time of shooting.

[Coaldust]

It is indeed Amp glow, It's a problem with all cams unless they are Peltier cooled and one that caused a lot of problems for my Astro imaging when using a Canon 300D.

It can be removed from an image using Dark frame subtraction but the glow will have destroyed any detail in the effected area.

[KennyC]

Oh ok, so it's not just me or the 5D. Thanks!

[Paul Shields]

Originally Posted by KennyC

Quiet forum, eh? Where's the Minolta users? Guess this IS my first post so I can't say much.

Welcome Kenny. Keep posting as you've started and I'm sure it will shake some more lurkers into contributing mode .

I agree with the various posters saying it is linked to sensor heat. I can't imagine there will be many times where you'll be taking a shot at 30secs at ISO 3200 so you should be OK in normal operating conditions.