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10-14-2007, 05:11 AM   #1
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Optimal settings for DA 16-45 on K10D

Calling on DA 16-45 owners,
(Im just a regular hobby photographer without a grasp of photo speak so my question may sound dumb but please indulge me).

I recently bought the DA 16-45. However, the images are almost always dark (atleast in comparison to the DA 50-200). When using the DA 16-45, I have tried to follow the instructions on page 161 of the operating manual and increase the compensation value however, I dont seem to be getting right.

I would like to know what your optimal settings are to get clear (un-dark) and sharp images. At what aperture do you get the best sharpness out of this lens and what EV value do you use

Thanks

10-14-2007, 05:52 AM   #2
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QuoteOriginally posted by jazzman Quote
I recently bought the DA 16-45. However, the images are almost always dark (atleast in comparison to the DA 50-200). When using the DA 16-45, I have tried to follow the instructions on page 161 of the operating manual and increase the compensation value however, I dont seem to be getting right.
It would be best if you could post some pictures for comparison.

One thought though: with a wide angle lens, it's very common to end up including a lot more sky than with a lens of longer focal length.

Since sky is often bright, it tends to fool the metering into underexposing a less bright part of the foreground subject, unless you use spot metering for the subject.

That might be one explanation, but as I say, it's very hard to know what's going on in the absence of some real examples. If you're finding the picture is dark all over even though the camera thinks it's correctly exposed, a comparison of the same scene at the same exposure and focal length with the kit lens (the 18-55) might be helpful.
10-14-2007, 06:02 AM   #3
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What mode are you shooting in?

M, Tv, Av, Sv etc etc...
10-14-2007, 06:44 AM   #4
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Thanks for your quick responses. Two pics on a grey day here. Shot in jpeg, using P mode. The first one is the 16-45 and the other is from the 50-200.

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View Picture EXIF
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10-14-2007, 07:27 AM   #5
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best sharpness appears to be f/5.6 for mine, but the lens is already pretty sharp at f/4.0
f/8.0 might be best for corners sharpness tho
10-14-2007, 07:41 AM   #6
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QuoteOriginally posted by jazzman Quote
Thanks for your quick responses. Two pics on a grey day here. Shot in jpeg, using P mode. The first one is the 16-45 and the other is from the 50-200.
Looking at your EXIF data, it appears that in the first shot you've exposed manually, using an EV compensation of 0.3. In the second one you left it on auto.

It boils down to an actual exposure of 1/125, F6.3 for the first one, and 1/125, F5.0 for the second one.

From the way the detail is rendered (assuming no post-capture manipulation), it looks like F6.3 was about right for the sky, and F5 was about right for the trees and water.

Inevitably, if part of the scene is much brighter than the rest, it won't be possible to get the whole frame exposed perfectly.

Last edited by ChrisA; 10-14-2007 at 08:00 AM.
10-14-2007, 10:09 AM   #7
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Yes there's some EV compensation and different setting in each shot. So these are not really a comparision of the 2 lenses. It's a metering issue and not a lens issue anyway.

If each shot is setup basically identically and there were drastic differences then I could see a problem:
True test for an outdoor nature shot would be:
Camera on tripod with all settings left untouched.
Both lenses set as the same focal length (one at 45mm the other at 50mm)
Shoot the exact same subject with the horizon in the same spot. Make the lens change and Test shots as close together in time as physically possible to avoid light changes.
Same f stop, shutter speed etc. 0 Ev

To look at these 2 shots and the settings in the EXIF data as well as the FOV of the shots both are exactly what I'd expect.
You used multi-segment metering and in the shot from the 16-45mm the tree line is much smaller in the shot and the metering system did a good job of balancing the sky and water which are the dominant features of the picture. It didn't try to meter the tree line as much since it's a smaller % of the shot. What the tree line correct then switch to spot or center weighted metering.

The second shot is the opposite. the tree line is large and the water is even larger with almost no sky. So the metering left the sky alone and balanced the metering for the water and tree line. As the tree line id basically dead center it did that section best.

All that being said these are very tough shots for the metering system. But there are some ways around it. 1) shot closer crops with the bright vs dark areas kept to a minimum.
2) shoot multi exposures on a single frame when there is no movement in the shot. there's another thread on right now dscussing that: https://www.pentaxforums.com/forums/general-pentax-photography/13261-barts-te...st-loving.html
3) Learn how to do HDR's for some of these technically difficult shots.
4) Use center weighted or spot metering more.

All that being said the shot from the 16-45 is the better shot. Once you have downloaded this shot you can easily adjust the levels to get the brightness you want. An underexposed shot is much easier to adjust than an overexposed one.The 16-45 shot exposed the water and sky accurately and you can enhance the shot a bit to bring out the colour in that shot.

Attachment 5296

This is a basic adjustment of the levels of that first shot.

Last edited by Peter Zack; 12-16-2007 at 08:52 AM.
10-15-2007, 06:43 AM   #8
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Thank you all for looking at my terrible shots and sharing tips all noted and I will be trying them out. I am so glad I asked for help.

10-15-2007, 09:01 AM   #9
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Hey nobody said the images were terrible. That's what we're all here for to learn how to tweak it a little better. Do you use any post processing software?
10-15-2007, 11:28 AM   #10
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FWIW - if you look up the 16-45 in various discussions all over the net, there's a school of thought that the lens under exposes by about 1/3 stop. Therefore, compensating ev is required.

My own experience is that this does tend to happen, only not entirely predictably in all situations using matrix metering. I use a K100D.
10-15-2007, 04:31 PM   #11
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Nothing wrong with the camera. The issue is with the lens. It tends to underexpose by between 0-3 to 0-5 EV with my copy. This I have confirmed this with both a K10D and K100D and matching it to an incident light reading with a Minolta Autometer V.
Dial in + EV compensation every time you use the lens.
10-17-2007, 03:48 AM   #12
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Quick comments to the other Posts

Peter Zack. Indeed no one said that the images were bad. I am my worst critic so I looked at the images and thought to myself, never ever think of giving up your day job to make a living out of photography (I have said that about most of my shots).

No I do not use any post processing software and I shoot jpeg (ask me why I bought the K10D if all I am doing is using it like a cell phone camera )

Nesster: Thanks for the advise.

Creampuff: By how much do you dial in the ev

On a serious note. This forum is very helpful (save for the endless fueling of LBA). I would also like to point out that it is very civilized (whatever that means). I plan to make small steps towards a better photographing experience (which includes interesting compositions, good exposure, post processing and all) so I will continue to learn from y'all
10-17-2007, 04:49 AM   #13
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I picked up this lens recently and love it. I doubt a third of a stop underexposure is going to make a huge difference, and is easy enough to fix after the fact. Better than overexposing -- at least there is some highlight detail to work with. If I just used a blanket EV bump I'd probably end up forgetting and leaving it on, blowing out all the shots I took with the next lens I put on...
10-17-2007, 06:36 AM   #14
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I also use +1/3 to +1/2 except when I want to be in auto-ISO mode. An easy way is to look at the replay of the image, soon you'll learn to know when the 'dark' thing is happening, and to dial in the compensation. Clicking over to the histogam helps as well. This is good practice with any lens if time permits, in order to compensate for how the camera defaults the exposure.

The worst underexposure I've got with the K100D is with a Lensbaby 1.0 - I've had to dial in 1.5 to 2 EV on the plus side. Don't know why, but that's how it goes.
10-17-2007, 05:04 PM   #15
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Using the 16-45, the metering mode selected also has a bearing on whether the camera gets the exposure correct. Matrix metering is particularly sensitive to bright light sources on the periphery, hence I tend to use center-weighted metering with this lens. Usually I dial in between +0.3 to as much as +0.7EV.

One radical means to correct this underexposure (which I learnt from a camera repair tech and which I don't recommend) is to open up the lens and just ever so slightly bend the the aperture coupling pin that is connected to the aperture blade lever, so that it will consistently "open up" a little when taking an exposure. Obviously this is a hit or miss affair.

Did this with an old Sigma wide angle that was consistently overexposing by 1.2 EV and it was perfect after that. Obviously you need to know what you are doing or you could end up with an usable lens.
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