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10-11-2012, 06:40 AM   #1
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TAV mode and RAW. Best strategy?

The K-30 has a handy new mode - TAV - which allows you to fix shutter time AND aperture, and the program chooses the right ISO for those values. You can also put a range for MIN/MAX ISO, for instance 100-3200 or 100-800. The program alerts if an ISO outside of this range is needed.

As we know RAW format offers quite a lot latitude in exposure, so that you can pull a decently lighted picture out of quite dark default picture.

My question is what is the optimal strategy, for instance
1) use low ISO range and possibly unerexposure (either letting TAV alert for this or adjusting EV range to underexposure so that TAV keeps quiet) 2) use greater ISO range so that you don't ever get underexposure. That may lead to some more noise I guess.

10-11-2012, 06:48 AM   #2
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Tav isn't new, it was on the k-5 also

The k-30 (and k-5) perform best in the shadow areas, while not as well in the highlight areas. In general, the camera sensor stores less data in the highlight areas anyways. So the preference is to expose to keep highlights from being blown - by underexposing. Since detail is more important than noise, this maximizes detail. Of course, if it's a highlight that you don't care about, no point in saving it.

Some people say that the k-30/k-5 have a maximum effective ISO of 3200 or something like that, and any higher ISO is electronically achieved - and so you can actually expose at ISO 3200 and bring it up in post to get the same effect.
10-11-2012, 06:49 AM   #3
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I just keep an eye on the ISO as it floats, and adjust A and T as required to keep it from getting too high or low. Keep the shutter speed as high as you can to avoid blurs (unless you want them). I find TAv extremely useful and use it most of the time. As you know, if you shoot RAW, you can afford to underexpose a little.

Your metering mode will make a big difference, too - I typically want center-weighted as I'm shooting a thing, not a scene most of the time.
10-11-2012, 07:02 AM   #4
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QuoteOriginally posted by JinDesu Quote
Tav isn't new, it was on the k-5 also
And the K10D, K20D and K-7.

In TAv mode, I set ISO to the range I want to stay within. If the camera warns me that my max ISO is too low, I can decide whether to boost ISO, or back off the aperture or shutter speed.

I don't see the point of shooting at a lower ISO and bumping up in post, there is no advantage for noise. Boosting exposure in post will also boost the noise. If you use the camera settings for noise reduction*, you will end up worse off, because the image will have less noise reduction applied at a lower ISO setting.

* I shoot raw, but I use the camera settings for noise reduction (they are imported by DCU4). The camera does a good job if NR is set to one of the lower settings. If I need more NR, I use Noiseware.


Last edited by audiobomber; 10-11-2012 at 07:08 AM.
10-11-2012, 07:08 AM   #5
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I have all my in-camera noise reduction turned off in my K5............do it in PP if necessary
10-11-2012, 07:12 AM   #6
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This mode has been there for a long time, at least since K10D.

It is particularly useful for wildlife, when you need to fix the aperture to control DOF and you need a certain speed to freeze motion, but the light changes dramatically as you move from open spaces, to the shade of trees.
10-11-2012, 07:22 AM   #7
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QuoteOriginally posted by drawbar Quote
The K-30 has a handy new mode - TAV
As others have noted: nothing new there...

QuoteQuote:
As we know RAW format offers quite a lot latitude in exposure, so that you can pull a decently lighted picture out of quite dark default picture.
Yes, and?

QuoteQuote:
My question is what is the optimal strategy, for instance
1) use low ISO range and possibly unerexposure (either letting TAV alert for this or adjusting EV range to underexposure so that TAV keeps quiet) 2) use greater ISO range so that you don't ever get underexposure. That may lead to some more noise I guess.
I think you need to a)read up on TAv and b)not get stuck in a "strategy".

Every situation is different but the fact that you are using TAv usually means that you are in less than optimal lighting conditions anyway. Decide for yourself what the maximum ISO is that you can still "treat" with noise reduction in your workflow and set the maximum to that - then leave it alone. I really see no point in setting the minimum other than the absolute minimum in the range anyway - chances are the camera will never use it.

"Lifting" an underexposed image shot at high ISO is like pushing high-sensitivity film: you get grain the size of golf-balls and your noise reduction program will start generating a lot of weird stuff. There definitely IS latitude in RAW but it is capped at the high end - you simply cannot squeeze orange juice out of a stone.

Using TAv is a wonderful invention that lets you control amount of (or lack of-) movement blur and DOF at the same time, at the price of potentially generating more noise when you don't want it. You do give up a bit of control and the quality of individual shots in a shoot may vary a bit too much unless lighting stays more or less constant.

I used TAv quite a lot on the K20D but I found that on the K-5 I end up using it less as I have more useable ISO-range to play with. The K30 should be similar to the K-5.
10-11-2012, 07:24 AM   #8
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I meant this TAV mode is new to me, as until recently I used to shoot mostly with Canon DSLR.

So as to the noise level increasing ISO when taking picture is about equivalent to boosting exposure in post? Accordinly nothing is gained by TAV underexposure as such (not counting the possible benefit to picture by higher shutter speed or smaller aperture).

10-11-2012, 07:35 AM   #9
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For me it boils down to what I'm shooting. I mostly shoot outdoors and use TAv quite a lot at ISO range of 100-1600. Even at 1600 the noise is quite low and easily dealt with post-processing. (I only shoot RAW). Indoors, especially portraits, is a whole different situation. I don't like TAv indoors as I like to control my ISO directly. In that case the Sv or Av settings work best for me.
My best advice is to try it all and you'll soon decide what works best for you!
10-11-2012, 07:39 AM   #10
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QuoteOriginally posted by drawbar Quote
I meant this TAV mode is new to me, as until recently I used to shoot mostly with Canon DSLR.

So as to the noise level increasing ISO when taking picture is about equivalent to boosting exposure in post? Accordinly nothing is gained by TAV underexposure as such (not counting the possible benefit to picture by higher shutter speed or smaller aperture).
Mind you - that's what some people say, that shooting ISOs higher than 3200 (or 1600, not sure) is not any better than bumping in post. I have not tried it, and it doesn't seem to be a big deal to me (I'd rather have an image I can review on the camera screen).

Tav mode is fantastic for the concept "the shot you get is the best shot". With the fantastic high ISO of the k-30/k-5, it's far more important to get the shutter speed and aperture that you WANT, than to sacrifice either for a little less noise. That's the whole idea of Tav.
10-11-2012, 07:40 AM   #11
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QuoteOriginally posted by demp10 Quote
This mode has been there for a long time, at least since K10D.
Yes, but only on the upper level cameras, the K-30 is the first time it's been on a midrange body. The K-01 doesn't have TAv, but allows auto ISO in M mode, which is similar but I believe does not allow Ev comp.

QuoteOriginally posted by demp10 Quote
It is particularly useful for wildlife, when you need to fix the aperture to control DOF and you need a certain speed to freeze motion, but the light changes dramatically as you move from open spaces, to the shade of trees.
I agree, that's one of two main scenarios where I use TAv. The other scenario is in low light, when I don't want the aperture to open all the way (e.g. FA 50mm 1.4), but need to maintain a shutter speed to prevent shake and fast enough for non-active people (typically 1/30s minimum).
10-11-2012, 09:19 AM   #12
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Who said that the maximum "effective" ISO is 3200? On the K-5 the native range is 100-12800, which is electronically extended down to 80 and up to 51K. I think the range on the K-30 is 100-12800 (-25600).

Although it IS true that higher in-camera ISOs appear to have more noise than "pushed" low ISOs, the post-processed noise is much more evident, since you're making all the pixels lighter (and therefore, the noise).
10-12-2012, 01:52 AM   #13
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What I'm wondering about... Is it for SURE that it's electronically enhanced(sensor-wise) up to 12800, and for SURE it's digitally enhanced to 25600? I mean - does anyone know with absolute certainty that that is the case?

And also, has nobody done tests to determine whether it's best to push a low ISO in PP than it is to just shoot at a higher ISO? I'd do these tests myself but don't have the experience/knowledge to do them yet. (I just bought Sagelight, but have NO IDEA what I'm doing with it yet - my experience in raw (or ANY image editing) is pretty much non-existent.. That's why I'm shooting RAW+JPG - at least until I learn more about dealing with raw. )


Thanks.
10-12-2012, 02:05 AM   #14
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QuoteOriginally posted by Hoggy Quote
What I'm wondering about... Is it for SURE that it's electronically enhanced(sensor-wise) up to 12800, and for SURE it's digitally enhanced to 25600? I mean - does anyone know with absolute certainty that that is the case?
Yes.

QuoteQuote:
And also, has nobody done tests to determine whether it's best to push a low ISO in PP than it is to just shoot at a higher ISO? I'd do these tests myself but don't have the experience/knowledge to do them yet.
Then I wonder why you'd bother with the issue to begin with? As someone else already mentioned: at extreme ISO values it's more important to get the shot to begin with. Once you get above ISO10000 things start to get flaky pretty darned fast - real keepers usually appear at ISO6400 and below. At those extremes of ISO10K and above, 10% more or less noise is not going to bother me.

QuoteQuote:
(I just bought Sagelight, but have NO IDEA what I'm doing with it yet - my experience in raw (or ANY image editing) is pretty much non-existent.. That's why I'm shooting RAW+JPG - at least until I learn more about dealing with raw. )
Now thàt is a solid way of learning: you start out by trying to equal the OOC jpeg (which is no mean feat with today's jpeg engines) and then go on trying to improve on them. Don't lose faith if at first you don't succeed!
10-12-2012, 10:55 AM   #15
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Imho

See what you can do in post processing to control noise. Find the highest value for which your software can compensate and set that as your high range value. I find that Lightroom can clean up any noise created at ISO 5,000. So that is my top setting for now.
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