User error? Re: Image degradation

Kegan

Kegan

Spam Assassin Mod
Hey guys,

I shot this performance last night at a bar - really really low lighting and it was sort of last minute to setup and shoot. I judged exposure from a Lilliput monitor (bad newbie mistake, I know) and shot at 1250 ISO. I think there was one small light over the stage.

Now, aside from my monitor battery smoking (it seems to be fine now after I replaced it) I thought the shoot went well other than a little low light. Some of the shots are brighter and cleaner than others and I'm trying to figure out why.

I moved the camera around a bit, but I think in the three screen captures I'm posting there wasn't too much movement and was in the general area.

clean.jpg


bad.jpg


bad2.jpg


bad3.jpg


Here's my thinking to what may have happened:

1) When I first set up the camera, in relation to the light source my lens was getting some sort of fill. When I moved the camera, it wasn't getting as much light and since my eyes had adjusted to bar lighting I didn't really notice.

2) The manual says that image degradation begins to happen as the camera heats up. I never got a heat warning (though I did get the buffer one a couple times, when snapping photos too...I was using a Kingston 32GB 133x - didn't feel like swapping the 8GB Extreme IVs)

3) It somehow got darker as the night wore on and I didn't notice...inside the bar?

I'm thinking it may be a combination of 1 + 2, but I'm really hoping this was all user error and poor exposing/picking a spot to film from that caused this terrible smudging and dark images..

Thanks a lot guys,

Kegan
 
Last edited:
Honestly, it just looks like lowlight tungsten(ish) balance @ 1250 ISO. Were you shooting at F3.5 ~ 4.5 aperture? As far as I've seen in my experience, this is pretty much why you get faster glass and don't shoot above 640 ISO (that's in extreme cases).
 
Hmm...I was shooting on a 50mm 1.8, wide open.

I have another picture I'm uploading and you can check it out in a second to see if it makes any sort of difference. In retrospect, I guess it was REALLY dark.

Kegan

EDIT: My ftp is being stupid and won't upload the whole picture - whatever, you get the point. Oh yes and I totally forgot to state what my question was in the first post. Why do some images appear better exposed and cleaner and then the rest look darker/lack detail when the settings remained the same.
 
Last edited:
Hunter007 said:
Hmm...I was shooting on a 50mm 1.8, wide open.

I have another picture I'm uploading and you can check it out in a second to see if it makes any sort of difference. In retrospect, I guess it was REALLY dark.

Kegan
Click to expand...

Good grief. That must've been extremely dark.

It didn't look like a wide open aperture because the DOF wasn't very thin but the OOF Areas in the new picture (fourth) are definitely tell-tale of the widest aperture. You really were shooting in the dark.
 
PHEW! I was hoping it was that. I'm curious then though - why is the first image so much brighter than the fourth? I don't believe lighting changed...

Maybe bumping the ISO up would have helped, but when you're shooting with no light I guess it really doesn't matter. I don't think much could have saved this heh. On a more positive note however, since the monitor made it look so bright I had a lot of people approach me impressed with the low light ability of the camera and I handed out a lot of business cards.

Kegan
 
Hunter007 said:
PHEW! I was hoping it was that. I'm curious then though - why is the first image so much brighter than the fourth? I don't believe lighting changed...

Maybe bumping the ISO up would have helped, but when you're shooting with no light I guess it really doesn't matter. I don't think much could have saved this heh. On a more positive note however, since the monitor made it look so bright I had a lot of people approach me impressed with the low light ability of the camera and I handed out a lot of business cards.

Kegan
Click to expand...

Actually, bumping the ISO up would've given you a worse image. 1250 is just bad with this camera in general and if you're white balanced improperly it exacerbates the image malfunctions.

If I had to guesstimate why the image in the first is so much brighter than the fourth it would be either composition changes or minor operator error (accidentally stopped down to 2 ~ 2.8).

What I mean by composition change would be: you moved the camera to the right and talent shifted as well. The segment of background that's now filling your frame is "darker" than what was once filling the frame before hand. So the perception of illumination is completely different.

I've had my 7Ds overheat a few times and it never changes exposure, although it does change the amount of visible noise and fixed patterns present.
 
Thanks a lot Kholi - that was exactly the sort of answer I was looking for. I agree with the composition change...very well could have been it. It's even possible that I accidentally stopped down, though I hardly touched the settings once I was all setup.

Hm, oh well - it was something I shot just because, not a paid gig so I can rest a little easier. Lessons learned.

As for the overheating with regards to the noise and fixed patterns - is the image affected prior to the warning or only after the warning? Just trying to figure out how to spot for these issues ahead of time so I know to either ice the camera down, take a mini break, etc.

Kegan
 
Hunter007 said:
Thanks a lot Kholi - that was exactly the sort of answer I was looking for. I agree with the composition change...very well could have been it. It's even possible that I accidentally stopped down, though I hardly touched the settings once I was all setup.
Click to expand...

It's very hard, with these cameras, to remember to watch out for accidental button pressing or iris shifting. I've done it a few times, but tend to catch it right as I go to shoot and notice my highlights look completely different. Turns out I may have shifted the Shutter or brushed the iris ring and stopped up or down from the half that I employed.

Just have to condition yourself to keep an eye out.

And, of course, a simple composition shift can and sometimes will affect how you perceive the exposure and exposed elements of an image.

As for the overheating with regards to the noise and fixed patterns - is the image affected prior to the warning or only after the warning? Just trying to figure out how to spot for these issues ahead of time so I know to either ice the camera down, take a mini break, etc.
Click to expand...

Well, if image degradation is going to happen due to overheating, I think it would happen gradually and not just instantly at a certain temperature. So, it would be an "over time" thing and the only real way to defeat that would be to have two or three cameras constantly switching off so that every time you used a new one it would be as cool as could be.

That's a major hassle. Just stay away from the overheating indicator, below 800 ISO (preferably 320 at max if you can) and you probably won't notice any difference.


Hm, oh well - it was something I shot just because, not a paid gig so I can rest a little easier. Lessons learned.


Kegan
Click to expand...

Indeed, the benefit of being able to go out on shoots for no money is that you still are looking for a result, and by looking for that result you're more apt to try and create something really nice. So, you'll learn faster under circumstances that demand more than just tinkering.
 
Auto Lighting Optimizer? I didn't even know that was a function...is that actually what its called?

Is it turned on or off out of the box?

Kegan
 
I believe it's automatically 'on' out of the box. This does add noise to your image by the way. Shut that bad boy off.
 
Just wanted to show you guys how part of the performance turned out (still really dark, but I didn't spend too much time on it):

IMPORTANT NOTICE: No media files are hosted on these forums. By clicking the link below you agree to view content from an external website. We can not be held responsible for the suitability or legality of this material. If the video does not play, wait a minute or try again later.
I AGREE


http://www.youtube.com/watch?v=TqKf0yWKA9E

Kegan

EDIT: I know the sound is bad - weird. I had a direct line-out from soundboard to H4n.
 
Last edited:
Haha you know...I never even noticed that. I think that was the angle of the keyboard, but it may have been the floor and I didn't adjust the legs.

Kegan
 
You must log in or register to reply here.
Back
Top