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03-11-2012, 07:11 PM   #1
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difference between Automatic exposures

After a few weeks of shooting my new K5 I'm just getting my head around the K5's modes but still struggling to understand some nuances. What is the difference in the Automatic Exposure we'd get in Program Line (which I understand) and the Automatic Exposure we'd get in Sv mode? Is the exposure that adjusts automatically in Sv mode the same as what's set in Program Line?

03-11-2012, 07:57 PM   #2
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I could be mistaken but if I remember, in SV the auto exposure mode will default to a higher shutter speed whenever possible. Use this at the races,

or whenever trying to grab shots of your 8 year old chasing the dog in the back yard.

They are both pretty much the same thing.

Unless you do want to show them as a blur and then you might want to default to AV, which is aperture priority.
03-11-2012, 10:08 PM   #3
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If that's the case, then can it be said that P and Sv are the same thing? The only difference being in P the Sensitivity is set on the ISO button and in Sv it's set on the Rear dial?

Seems a bit redundant.

Or, am I missing something?
03-11-2012, 11:58 PM   #4
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No, it does seem a little redundant but when you use SV mode you are manually selecting the shutter speed you want, and then the camera decides the best aperture to use. I do not believe that it will adjust ISO but I am not real sure. If the camera is on Auto ISO and you have given it a range of ISO values to work with then it may adjust your ISO as well.

In Program mode the camera is making all the decisions for you. You cannot tell it to use a specific shutter speed in Program Mode, but when you tell it to default to SV (shutter), then it will try to keep your shutter speed as high as possible to avoid camera shake, rather than immediately start to drop it in favor of something else. And yes, it will certainly use aperture and ISO to try to maintain that higher shutter speed. What Pentax is trying to do with these options is allow you some way to influence how the camera is making its decisions for you in Program Mode.

I think your other two options are AV (aperture priority) and MTF. If you look I think that the manual actually shows some information like graphs that show you how it makes the decisions in SV and AV priority. Since MTF is different for each lens I think you would have to look at each lenses specific MTF chart to see the decision making logic the camera is using.

03-12-2012, 12:07 AM   #5
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Remember, in SV mode the camera will not change the shutter speed you select. It will work everything else around that specific shutter speed. Eventually, if it thinks that it cannot take a good picture at the particular shutter speed no matter what other options it selects, it will give you all kinds of warnings. Red flashing lights, sirens, who knows. But it will not change the shutter speed you chose.

In Program Mode you have no control over the actual shutter speed and, although the camera will try to keep it as fast as it can for as long as it can, eventually it will change it and slow it down if it decides it needs more light to get a proper exposure.

Summary...in SV Mode, you are in control of a very specific shutter speed you have chosen and the camera will not change it. In Program Mode you can suggest what you would prefer, but in the end you don't have control, the camera does, and it will change anything it can to get the picture, even your shutter speed in the end.
03-12-2012, 03:47 AM   #6
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Pioneer, you are confusing Sv and Tv mode.
Tv mode is the one you describe where you select the shutter-speed and the camera controls aperture and possibly iso.
Sv mode is 'sensitivity' priority mode: you select the iso sensitivity, and the camera selects shutter speed and aperture.

To answer the original question: yes, that's kind of redundant, as you can get the same result using P-mode with any ISO setting other then 'auto'.
P mode (or hyper-P mode as Pentax calls it usually) is also able to act as Av or Tv mode, just by turning the front/rear e-dial, it temporary changes the way it works and sets a chosen aperture (rear dial) or shutter speed (front dial).
03-12-2012, 04:09 AM   #7
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Yeah, I was aware that from P we can jump to Av and Tv with the dials (which I think is clever design). I guess Sv just being a button re-assignment away from P keeps things consistent across the board.

it seems, at least in my mind, that "Hyper" means we can jump to other modes. But then what does the "v" stand for in the Av, Tv, and Sv?

..."value"?

I suppose it's anybody's guess.
03-12-2012, 06:53 AM   #8
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The "v" does stand for "value". Read "Changing the Exposure Mode" section of K5 operating manual. Begins with a helpful chart on page 100. Forums are excellent for lots of reasons but not a substitute for your operating manual,a good book on "Exposure" and practice.

There are lots of good books on exposure. A starting suggestion for you is "Exposure Photo Workshop Second Edition" by Jeff Wignall. Also "Digital Exposure Handbook" by Ross Hoddinott. Enjoy your new K5.


Last edited by jcp5; 03-12-2012 at 08:58 AM.
03-12-2012, 10:10 AM   #9
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The manual hints at how it works...'when P-Line is selected as being assigned to the greeen button setting via the menu option {rec mode 3} - for P/Sv mode, and TAv/M mode, exposure is regulated according to the set program line'.

It sort of makes it sound like the K-5 might be using something else IF P-Line is NOT assigned to the green button (although P should use the P-Line 'all the time' - unless it is manually over-riden using Progam shift or hyper modes), but doesn't explain it more. I figure maybe the emphasis could always be on faster shutter speeds, if the chosen P-line setting is not actually used

Last edited by jmg257; 03-12-2012 at 10:21 AM.
03-12-2012, 11:03 AM   #10
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Well, jcp5, I agree, no substitute for the manual, a book, and experience.

I've had that chart bookmarked, actually. And now when I look again I do see on *one* of the seven column headers the use of the word "value". It was easy to miss, and definitely not consistent used throughout the manual. Speaking of that chart, the legend shows the meaning of both an "x" and a checkmark but doesn't explain the "-" that also appears in two cells of the table. I'm guessing that means "Not Applicable" but I'm not sure.

I've got a handful of about 10 photography books leftover from my days when I used to shoot my F3, so I've got the "good book" suggestion covered but thanks for the tip, always room for one more in my photography library.

As far as experience I'm at about 4,000 shots taken in less than three weeks. I'm a busy boy, 'eh?

I'm just thankful Pentax has such a vibrant forum to pick up the slack where this manual leaves off--it's adequate *at best*.
03-12-2012, 03:54 PM   #11
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Sorry about the mixup folks.
03-12-2012, 04:33 PM   #12
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No worries, buddy. Some of those acronyms aren't exactly intuitive when they're ambigous like that. But I knew what you meant.
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