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05-06-2009, 08:08 PM   #1
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New K20D User - Green and P setting images seem dark / muddy

I am embarrassed to even post this question here because I'm sure that this is user error on my part, but if some more experienced photographers can take pity on me, I will be forever grateful!

My first 35mm camera was a Pentax back in the 1970s, and later I moved on to a Ricoh body that accepted my Pentax lenses. I had put off buying a digital SLR camera for years, but finally made the plunge last week and bought a K20D. Being that I am still getting used to the camera, I wanted to just take some images on as much of an automatic setting as I could, so I've been experimenting with the Green and P settings using the stock Pentax 18-55mm lens that came with the kit. The only problem I've noticed is the images indoors seem dark and almost muddy, compared with the images I've taken on other cheaper digital cameras on full auto setting.

I do some video work for Buffalo Wild Wings however they wanted me to take some still images at one of their restaurants this morning, so I thought it would be a good try out for the Pentax K20D. However, even after lighting a scene with a nice softbox, the images all seemed considerably darker, and muddier, than what I was seeing in the liveview LCD display, almost 2 stops darker. Nothing I did seemed to bring that image level back up: no matter what I was seeing on the LCD, the captured image was always dark and the colors muddy in the P or Green settings. The only setting that gave me a bright image was bulb, but that was inconsistent, sometimes bright, sometimes completely dark, and I was unfamiliar with that particular setting and didn't want to be reading the manual in front of the client. So I ended up giving up and taking the rest of my images with a Panasonic Lumix DMC-FZ8 which took wonderfully bright images that matched what I was seeing on the monitor.

So, I am sure I am doing something wrong ... what is it? Is there not a more or less "full auto" mode that I can use while getting used to this camera, and if green is that setting, like the manual says, why do my images look so dark? Any assistance you can provide for a dumb video guy trying to get back into quality photography again would be much appreciated!

A follow up: I am noticing that as I use the zoom lens, when I have it full wide, the picture seems bright as the the screen ... and it is showing an F stop of F3.5. However, as I zoom in, it shows the F stop changing to F5.6, and the resulting image is dark ... just like I was encountering earlier today! So the zoom lens is controlling the F stop setting?? Why is that?


Last edited by eznewmedia; 05-06-2009 at 08:15 PM.
05-06-2009, 08:14 PM   #2
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It's pretty normal for first time DSLR users to notice this. Film camera meters tend to be not as conservative as digital camera meters, because film doesn't "clip" highlights the way digital does. P&S cameras are less likely to try to protect highights, and they also usually apply pretty heavy-handed exposure curves to bring out shadow detail. DSLR's tend to be more "what you see is what you get" - no fancy processing to lighten shadows (unless you use the "D-Range" feature). Also, compared to other DSLR's, Pentax tends to try harder to avoid clipping highlights, which results in darker pictures overall when there ar ebright highlights that are in danger of clipping.

All this means you need to get used to how the camera meters and learn when to use exposure compensation, and/or learn when to use substitute metering - finding a different subject (like a gray card) to meter from that will yield the exposure you want.
05-06-2009, 08:15 PM   #3
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There are lots of things that could cause unexpected results if you are unfamiliar with the camera. However, if your scene was predominately bright (ie: white) you will get underexposed looking images. You would need to dial in some positive exposure compensation to correct for this. Also, if you don't manually correct for white balance you are likely to get "muddy" looking images under tungsten light. Bulb mode is only really useful for long exposures over 30 seconds.
05-06-2009, 08:24 PM   #4
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Thanks for the very quick feedback! I added one other comment to my post before you responded, so I will repost my additional observation: I am noticing that as I use the included zoom lens, when I have it full wide, the captured picture seems as bright as the the screen ... and it is showing an F stop of F3.5. However, as I zoom in, it shows the F stop changing to F5.6, and the resulting captured image is dark ... just like I was encountering earlier today! So the zoom lens is controlling the F stop setting?? Why is that?

05-06-2009, 08:45 PM   #5
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Aperture is related to focal length (I can't remember it all at the moment - I think it's usually written f2.8 and the f really means focal length). The aperture blade opening of a 50mm lens at 2.8 will be a different diameter than a 200mm lens set to f2.8. So designing a zoom lens with a constant aperture is a lot more complex than what you would think. The inexpensive lenses like the kit lens don't try to do that - the maximum aperture (smallest f number) changes through it's zoom range.
05-06-2009, 09:01 PM   #6
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I guess that makes sense, though I wonder why the camera doesn't compensate for the higher F stop when zoomed in while in green mode. That dopey Panasonic looks exactly same as far as picture brightness throughout its entire 12x optical zoom range.

Also, just to test things, I put one of my older zoom lenses from my SLR Ricoh camera on this camera ... and no matter where I zoomed, the F stop stayed at 2.8 ... and the picture was MUCH brighter than the supplied kit lens that came with the K20D when zoomed all the way in.
05-06-2009, 09:11 PM   #7
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A lot depends on which metering mode you are in (spot, center weight or matrix). As you zoom in the scene changes and so will your exposure. If you post a photo and the setting you used we can probably help you with suggestions on which metering mode would have been best.

Hope that helps!
John
05-06-2009, 09:48 PM   #8
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To add to that, I'd really like to see a pair of photos of the same scene, one from the FZ8 and one from the K20D, where the K20D failed you. Preferably with full EXIF intact.

05-07-2009, 05:52 AM   #9
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From what I'm hearing you say it sounds like you might have been shooting in either Manual (M), Shutter Priority (Tv) or Bulb (B) mode. Otherwise, your K20D should have given you the same basic exposure at any focal length/aperture combination. I agree that you need to post some photos with EXIF data intact if you want to get any real help.
05-07-2009, 07:22 AM   #10
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QuoteOriginally posted by eznewmedia Quote
....The only problem I've noticed is the images indoors seem dark and almost muddy, compared with the images I've taken on other cheaper digital cameras on full auto setting.
I think Mark Sabatella's excellent answer may be right on target: This is more or less the way digital SLRs work. The Pentax K10D/K20D in particular tries to avoid clipping highlights. I tend to work with one-third of a stop ( EV +1/3) adjustment to the meter, as my default.

I would also agree with Robert Donovan's comment that you should be seeing the same result in any mode, for a given aperture, shutter speed + ISO. I mean, it's the same meter no matter what mode. I assume you mentioned Green and P in the subject title because these are the modes that you've been using.

I have a few suggestions.

First, it sounds like you need to get familiar with the +/- button. You didn't mention it in your post and I bet most of us reading your post were wondering if you tried adjusting the meter.

Second, try different metering modes. I used to favor center-weighted matrix metering, but lately I've been using full-matrix metering with good results. Spot metering I use only for special cases and I don't encounter many special cases. I would suggest switching to full matrix metering.

Third, when you review a shot in the monitor on the back of the camera, ignore the photo itself. There's just not enough detail there to assess the photo well. What is helpful is to turn on blinkies and/or the histogram and learn how to use them. To durn "blinkies" on, go to Menu > Playback > Playback Display and put an x in the Bright/Dark area box. I find this the single most useful part of a quick review of a photo. It tells me at a glance whether there IS either bright or dark clipping and - most important - WHAT'S GETTING CLIPPED. The histogram is usesful too as it tells you what's going on in the middle of the exposure range. But of the two, I find blinkies more useful while shooting.

Of course it's possible (theoretically) that the meter in your new camera is broken, but it's unlikely, and it doesn't sound like you're familiar enough with the camera to make that diagnosis.


QuoteQuote:
.... I was unfamiliar with that particular setting and didn't want to be reading the manual in front of the client.
Yeah. That's why (as you know now) it's a really good idea to get very familiar with new equipment before taking it on a shoot. Sounds like you're new to digital SLRs generally. They are different from shooting film. One of the best things about digital is that it's really easy to practice, practice, practice.



QuoteQuote:
So, I am sure I am doing something wrong ... what is it? Is there not a more or less "full auto" mode that I can use while getting used to this camera, and if green is that setting, like the manual says, why do my images look so dark? Any assistance you can provide for a dumb video guy trying to get back into quality photography again would be much appreciated!
I urge you to abandon the idea of getting familiar with the camera in FULL AUTO mode and jump immediately to taking control, at least to some degree. M mode is really easy to use. Set a reasonable ISO for the scene (use ISO 400 if you aren't sure). Click the green button and shoot. Review the exposure, consider the aperture and shutter speed that the camera gave you when you hit the green button, and learn from that. Adjust as necessary. OR learn to use the K20D's hyperprogram (P) mode, which I think is fantastic. I used to shoot M almost exclusively but I use P more and more and I'm really liking it. One advantage of P is that you can switch into effective aperture-priority or effective shutter-priority mode simply by adjusting either the rear or front e-dial, and when you do that, the other setting will be adjusted by the camera automatically. For example, if the camera's default settings in P are f/5.6 @ 1/200th sec, and you decide that you'd like less depth of field, you can turn the rear (aperture) e-dial to f/2.8 and the camera will automatically adjust the shutter speed to 1/800th sec.

You're of course more than welcome to use the camera any way you like. But I don't see how anybody learns anything shooting in green mode. The way to learn is to take control and do some practice shooting where you can afford to experiment, make mistakes, encounter problems and figure out how to solve them.


QuoteQuote:
A follow up: I am noticing that as I use the zoom lens, when I have it full wide, the picture seems bright as the the screen ... and it is showing an F stop of F3.5. However, as I zoom in, it shows the F stop changing to F5.6, and the resulting image is dark ... just like I was encountering earlier today! So the zoom lens is controlling the F stop setting?? Why is that?
You're using a zoom lens with a variable aperture. It has a maximum f/3.5 aperture at 18mm, but when you zoom out to 55mm or whatever, the maximum aperture gets smaller. The lens isn't exactly controlling your aperture setting in the camera. It's simply sending info to the camera saying, "Well, now that he's zoomed to 55mm, I can't go as wide as f/3.5 any more. Best I can do is f/5.6. Deal with it." And the camera deals with it by adjusting your settings. This is a basic fact of life with zoom lenses. There are zooms with fixed maximum apertures but they cost more. When you're buying a lens, notice the info provided in the basic description of the lens:

18-55 f/3.5-5.6
16-45 f/4

The first lens has a variable max aperture; the second (which mentions just 1 aperture) has a fixed f/4 through its zoom range.

Hope this helps.

Will
05-07-2009, 09:33 AM   #11
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AE-L

A neat trick is the metering locking function using the AE-L button with spot metering.

This might sometimes be quicker than working in manual.
05-07-2009, 01:38 PM   #12
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QuoteQuote:
I urge you to abandon the idea of getting familiar with the camera in FULL AUTO mode and jump immediately to taking control, at least to some degree. M mode is really easy to use. Set a reasonable ISO for the scene (use ISO 400 if you aren't sure).
I see people recommend avoiding auto a lot, but little justification for it. When you're ready to learn the details, then absolutely experiment with the other modes, but the auto stuff is there for a reason and is supposed to work consistently. Even if you know the details, auto gets them out of the way so you can just take the picture without calculating settings in your head. Something as apparently simple as "reasonable ISO for the scene" depends on a lot of variables you have to already know how to deal with.

There are good reasons for controlling all the settings manually at times, but auto is supposed to work and is supposed to do so with little trouble. It's the fastest and simplest way to get a properly exposed picture. Avoiding it just for the sake of avoiding it doesn't seem like sound advice to me. It's like trying to troubleshoot a simple situation by making it 4 times more complicated...

(I'm not picking on you Will, especially since you gave an example of why you'd choose a particular mode and how you use it. I just see this theme a lot, and it's particularly irritating when it's given to someone who wants to use auto to begin with.)
05-07-2009, 02:35 PM   #13
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QuoteOriginally posted by eznewmedia Quote
I guess that makes sense, though I wonder why the camera doesn't compensate for the higher F stop when zoomed in while in green mode.
To some extent it does. You shouldn't be seeing differences of more than a fraction of a stop. However, you should be aware that as you zoom in, you are presenting a different scene to the camera, so it might well choose to meter it differently. Try the experiment shooting a featureless wall and you should see very little difference. But if you are shooting the lens at its widest aperture, then it is true that the stated maximum apertures are just approximations (rounded to the nearest half stop).

QuoteQuote:
That dopey Panasonic looks exactly same as far as picture brightness throughout its entire 12x optical zoom range.
Most likely, you weren't shooting it at its widest aperture. If you let the lens stop down - say by choosing f/8, or by shooting in an environment where the camera can choose f/8 - then it should be able to to set the aperture more exactly. It's only "wide open" that normally introduces some variance across the zoom range.

QuoteQuote:
Also, just to test things, I put one of my older zoom lenses from my SLR Ricoh camera on this camera ... and no matter where I zoomed, the F stop stayed at 2.8
Is that a lens with an aperture ring? The ring might have stayed at f/2.8, but that doesn't mean the aperture *really* stayed at f/2.8.

QuoteQuote:
... and the picture was MUCH brighter than the supplied kit lens that came with the K20D when zoomed all the way in.
I think you need to post some pictures (with EXIF intact) to demonstrate what you are talking about. I you are doing things correctly, there shouldn't be more than a small fraction of a stop difference in brightness.

BTW, you aren't by any chance shooting flash, are you? That opens up a whole different set of issues, with different potential explanations for what you are seeing. And if you're shooting with flash on one camera but not with the other, that in itself pretty much oud explain a lot of differences right there.

Last edited by Marc Sabatella; 05-07-2009 at 02:50 PM.
05-07-2009, 02:48 PM   #14
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QuoteOriginally posted by Quension Quote
I see people recommend avoiding auto a lot, but little justification for it.
I'll give a (half-hearted) justification for it, then :-).

I don't really recommend beginners avoid auto, but to the extent the advice makes sense, it is precisely because of situations like this - situations where auto does *not* necessarily do the right thing. People need to understand that shooting a white dress is *supposed* to require positive exposure compensation; same with shooting a backlit subject. Or that shooting a night scene or a black cat often requires negative compensation. Otherwise they'll wonder why their pictures don't look how they want them to. True, you can learn to use exposure compensation in P mode, but that just puts off the next series of questions - why isn't more of the picture in focus (DOF too shallow), why is there motion blur (shutter speed too slow), etc. So then you need to learn about Av mode and Tv mode. And by that time, your mind is swimming with lots of information about how to get such-and-such a result in such-and-such a mdoe, and which mode is best for what situation, etc. With no understanding of the underlying principles, the camera will seem like a mysterious black box where you have remember arcane combinations of button presses to make it do what you want. Whereas it is actually a very simple and logical tool that behaves very predictably once you understand the principles behind it. And once you understand those principles, it becomes much easier to get the results you want, because you'll know exactly why you aren't already getting them.

Put another way: if you don't understand the principles, you are stuck asking a whole series of questions that basically work out to "what buttons do I push to get the result I want in situation A", then the next day "what buttons do I push to get the result I want in situation B", and so on and so on - accumulating long laundry list of seemingly unrelated workarounds to seeming unrelated problems. Whereas with an understanding of exposure, these questions basically answer themselves.

So I figure it's all well and good to start off using auto, but the moment you start being dissatisfied with the results and wondering how to improve on them, that's the moment it makes sense to actually reach an understanding of the issues rather than go down the road of learning seemingly random workarounds to seemingly random problems.

For these reasons, I do think it good to learn about how the exposure parameters relate, how the lens affects the possibilities, etc. Whether you do this by simply reading (and maybe doing a little experimentation to see the results in practice) or actually *using* manual mode in real life doesn't really matter.
05-07-2009, 02:53 PM   #15
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QuoteOriginally posted by Quension Quote
I see people recommend avoiding auto a lot, but little justification for it. ....
Quension, thanks for not picking on me. I'm married and have three daughters so I get picked on plenty already. : ^)

But I gave a reason for not using green mode: It teaches you nothing. And it seems pretty clear that the OP has some things to learn. God knows, so do I.

And I also gave a reason for not avoiding - for NOT NOT using - one of the other modes: the other modes are almost as easy as green mode. I recommended M as the best learning mode, in part because it gives you the opportunity to make the most interesting mistakes, the kinds of mistakes you can really learn from. But I also mentioned P, which is no more difficult to use than green mode on the K20D but does give you the option of stepping in effortlessly and taking control.

I have never been a snob about this subject. It is true that it's possible to take a properly exposed photo in green mode - and I have more proof than I'm ever going to share that you can take bad exposures in M! But I am quite sure that you can't take a LOT of proper exposures in full auto. There are just too many ways to fake out the camera's meter. If you want consistently good results, you have to show the camera who's boss. You can do it with M, or Av or Tv, or on a K10D/K20D, you can do it in the brilliant hyperprogram or P mode (which gives you access to green, Av and Tv without the need to move the mode dial ever).

Will
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