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11-19-2015, 09:19 AM   #1
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K3 EV Compensation When Why How

I shoot exclusively in Raw and post process in Lightroom. As the old expression goes "a little bit of knowledge can be dangerous"; thus, I would like to get a better understanding of under what conditions should EV Compensation be used and to what extent to achieve optimum results. I know that beauty is in the eye of the beholder, so optimum may be somewhat subjective, but I would like to hear various opinions and approaches that I can use as jumping off points for my own experimentation. I seem to recall that the K3 has a slight tendency for overexposure and some recommend compensating. Have others heard this and if compensating to what degree?
I have had various Pentax cameras from film, to K10D and presently a K3, which I received last week. So far everything I see, read, and have experienced with the K3 tell me that this is a special camera. Thanks in advance for your input and feedback!

11-19-2015, 09:51 AM   #3
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QuoteOriginally posted by MRCDH Quote
I shoot exclusively in Raw and post process in Lightroom. As the old expression goes "a little bit of knowledge can be dangerous"; thus, I would like to get a better understanding of under what conditions should EV Compensation be used and to what extent to achieve optimum results. I know that beauty is in the eye of the beholder, so optimum may be somewhat subjective, but I would like to hear various opinions and approaches that I can use as jumping off points for my own experimentation. I seem to recall that the K3 has a slight tendency for overexposure and some recommend compensating. Have others heard this and if compensating to what degree?
I have had various Pentax cameras from film, to K10D and presently a K3, which I received last week. So far everything I see, read, and have experienced with the K3 tell me that this is a special camera. Thanks in advance for your input and feedback!
If you camera has a tendency to underexpose, you can use EV comp to tell the camera to constantly overexpose so that the image comes out how you like it (or the other way around for overexposing). I find the K-3 to be pretty spot on, especially compared to my old K-20d that needed +0.7 comp.

I also use it whenever I know I'm shooting a mostly dark or mostly light scene and I know the scene will trick up the metering. If I'm shooting dark, then I use -1.3 ev or the other way around for a light scene like snow.
11-19-2015, 10:49 AM   #4
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The short answer is that you use EV when the automated meter system does not provide the exposure that suits how your visualize your subject. How to do this is in the user manual. The specifics vary between camera models. Your other option is to shoot in Manual mode and nudge aperture and/or shutter speed to suit.

Common use cases include:
  • Strong backlighting
  • Deep shadows of critical importance
  • Blown detail in clouds
  • Blown detail in pure bright colors due to channel clipping
  • Edit: Forgot to include snow and bright sand to the list. Both will usually meter 1-2 stops less light than is appropriate.*

FWIW...Exposure comp is a by-product of exposure automation. In the years before the camera was choosing settings for you, compensation was applied the old-fashioned way...when you set the aperture and shutter speed.


Steve

* As noted in other comments on this thread, when and why to use EC is all bound up with exposure theory and how the metering systems work. A good book or set of tutorials on exposure are very helpful. I favor the tutorials on the Cambridge in Color Web site (http://www.cambridgeincolour.com/learn-photography-concepts.htm). Brian Peterson's book is sort of the standard text (http://www.amazon.com/Understanding-Exposure-3rd-Edition-Photographs/dp/0817439390). I learned the nitty-gritty from Ansel Adams, "The Negative". His approach is more technical, but the principles can be broadly applied. Your public library should either have or be able to get a copy.


Last edited by stevebrot; 11-19-2015 at 11:22 AM.
11-19-2015, 11:04 AM   #5
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A slightly simplified explanation to get the concept (different metering modes might change this somewhat):

The meter in any camera want to tell the camera to expose so that the image averages to the equivalence of middle-gray.
If the scene you are shooting isn't a typical daylight scene, that level of brightness might not give you the exposure you like.

The most common scenario I come across is shooting on snow. Because it is so bright, I don't want the camera to expose my photo to be mid-gray because snow is not gray, it is white.

So I'll dial up the compensation (+/-) to overexpose by .5 to 1.5 stops to make the snow white.

Or if I'm shooting in low light and want the photo to look like it was shot in low light, I'd dial down the compensation so the photo looks like a night shot. This can also help keep the shutter fast enough to shoot handheld while not using compensation would need a slower one.

Finally, if you have a scene that is mostly mid-toned like a forest or mountain scene with bright clouds in the sky, the meter might set your exposure correctly for the forest but the clouds will overexpose, losing detail to the blown out part of the shot. This is often called a hot spot. To get around this, you could dial the compensation down, underexposing the forest and getting a good cloud exposure. Then when processing the shot you can raise the shadows to bring back out the forest detail.
11-19-2015, 11:05 AM   #6
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you can also use it to "bias" your bracketing. For example if you dial in -1 EV compensation and shoot a bracket of five with +2, +1, 0, -1, -2 bracketing, you'll end up with +1, 0, -1, -2, -3 exposures. This would give you very nice sunset detail (for example) and still give you pretty decent shadow detail.

Michael
11-19-2015, 11:08 AM   #7
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QuoteOriginally posted by mattb123 Quote
The most common scenario I come across is shooting on snow.
Ha! I forgot to include snow/beach in the list. I guess that shows how long it has been since I have shot either


Steve
11-19-2015, 11:28 AM   #8
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I use it regularly. I start with center weighted exposure, then adjust up or down. I shoot wildlife mostly, and set a -ev for white highlights, for example -1.3 for osprey in the morning sun. I'll adjust +.7 or +1 for birds against a cloudy sky, +.3 against blue sky. The fall light typically needs -.3 to not blow highlights.

11-19-2015, 12:43 PM   #9
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when i do night city skyline shooting, if there is a particularly bright part of a building or strongly lit section that i do not want to blow out, i will dial in some underexposure, such as -1 to -2ev just to keep those under control.

I also use it as mentioned by Michael above as a bias for a 5-exposure bracket when the sun is in the frame if i want to retain reasonable highlight control of the sun in the darkest bracketed frame.
11-20-2015, 07:27 AM   #10
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QuoteOriginally posted by enoeske Quote
If you camera has a tendency to underexpose, you can use EV comp to tell the camera to constantly overexpose so that the image comes out how you like it (or the other way around for overexposing). I find the K-3 to be pretty spot on, especially compared to my old K-20d that needed +0.7 comp.

I also use it whenever I know I'm shooting a mostly dark or mostly light scene and I know the scene will trick up the metering. If I'm shooting dark, then I use -1.3 ev or the other way around for a light scene like snow.
I have not experienced the exposure problem, I have read in one the the reviews of the camera that it tends lean in the direction of more exposure. I just put that observation out there to see if anyone had a similar experience. Thanks for your input.

---------- Post added 11-20-15 at 07:34 AM ----------

Thanks for the suggested readings; I will take a look at them this weekend and experiment with what is suggested. Thanks for your input.

---------- Post added 11-20-15 at 07:37 AM ----------

QuoteOriginally posted by stevebrot Quote
The short answer is that you use EV when the automated meter system does not provide the exposure that suits how your visualize your subject. How to do this is in the user manual. The specifics vary between camera models. Your other option is to shoot in Manual mode and nudge aperture and/or shutter speed to suit.

Common use cases include:
  • Strong backlighting
  • Deep shadows of critical importance
  • Blown detail in clouds
  • Blown detail in pure bright colors due to channel clipping
  • Edit: Forgot to include snow and bright sand to the list. Both will usually meter 1-2 stops less light than is appropriate.*

FWIW...Exposure comp is a by-product of exposure automation. In the years before the camera was choosing settings for you, compensation was applied the old-fashioned way...when you set the aperture and shutter speed.


Steve

* As noted in other comments on this thread, when and why to use EC is all bound up with exposure theory and how the metering systems work. A good book or set of tutorials on exposure are very helpful. I favor the tutorials on the Cambridge in Color Web site (Learn Photography Concepts). Brian Peterson's book is sort of the standard text (http://www.amazon.com/Understanding-Exposure-3rd-Edition-Photographs/dp/0817439390). I learned the nitty-gritty from Ansel Adams, "The Negative". His approach is more technical, but the principles can be broadly applied. Your public library should either have or be able to get a copy.
Steve thanks for the feedback and suggested references. I will check out the reference material you suggested this weekend.

---------- Post added 11-20-15 at 07:41 AM ----------

QuoteOriginally posted by mattb123 Quote
A slightly simplified explanation to get the concept (different metering modes might change this somewhat):

The meter in any camera want to tell the camera to expose so that the image averages to the equivalence of middle-gray.
If the scene you are shooting isn't a typical daylight scene, that level of brightness might not give you the exposure you like.

The most common scenario I come across is shooting on snow. Because it is so bright, I don't want the camera to expose my photo to be mid-gray because snow is not gray, it is white.

So I'll dial up the compensation (+/-) to overexpose by .5 to 1.5 stops to make the snow white.

Or if I'm shooting in low light and want the photo to look like it was shot in low light, I'd dial down the compensation so the photo looks like a night shot. This can also help keep the shutter fast enough to shoot handheld while not using compensation would need a slower one.

Finally, if you have a scene that is mostly mid-toned like a forest or mountain scene with bright clouds in the sky, the meter might set your exposure correctly for the forest but the clouds will overexpose, losing detail to the blown out part of the shot. This is often called a hot spot. To get around this, you could dial the compensation down, underexposing the forest and getting a good cloud exposure. Then when processing the shot you can raise the shadows to bring back out the forest detail.
Matt, thanks for the input; that is an interesting point on shooting snow or very bright environments to not have a wasted out appearance and be more natural.

---------- Post added 11-20-15 at 07:46 AM ----------

QuoteOriginally posted by MJSfoto1956 Quote
you can also use it to "bias" your bracketing. For example if you dial in -1 EV compensation and shoot a bracket of five with +2, +1, 0, -1, -2 bracketing, you'll end up with +1, 0, -1, -2, -3 exposures. This would give you very nice sunset detail (for example) and still give you pretty decent shadow detail.

Michael
MJ, I haven't done much with bracketing although is sound like it would really enhance a shot; I will make a point of experimenting with this to come up with varied and more interesting photos.

---------- Post added 11-20-15 at 07:49 AM ----------

QuoteOriginally posted by derekkite Quote
I use it regularly. I start with center weighted exposure, then adjust up or down. I shoot wildlife mostly, and set a -ev for white highlights, for example -1.3 for osprey in the morning sun. I'll adjust +.7 or +1 for birds against a cloudy sky, +.3 against blue sky. The fall light typically needs -.3 to not blow highlights.
Derek, thanks for your feedback and the specifics where you utililze the EV compensation; I will keep your suggestions in minds when shooting under similar conditions.

---------- Post added 11-20-15 at 07:51 AM ----------

QuoteOriginally posted by mikeSF Quote
when i do night city skyline shooting, if there is a particularly bright part of a building or strongly lit section that i do not want to blow out, i will dial in some underexposure, such as -1 to -2ev just to keep those under control.

I also use it as mentioned by Michael above as a bias for a 5-exposure bracket when the sun is in the frame if i want to retain reasonable highlight control of the sun in the darkest bracketed frame.
Mike, thanks for your suggestions; I took a look at some of your photos and you have really captured some great pictures of the San Francisco area.

Last edited by MRCDH; 11-20-2015 at 07:33 AM.
11-21-2015, 09:51 PM   #11
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Here you go, great video explaining it.

11-23-2015, 10:07 AM   #12
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First of all, I think it is a good idea to shoot various scenes - especially high DR scenes outdoors - and use the exposure bracketing feature to determine what exposures work best for your camera.

Second, I can confirm with certainty that my K-3 has a tendency to expose to the right (overexpose), especially in challenging situations. I've had Pentax bodies that tend to slightly underexpose (*istD), ones that seem to be spot on (K-01/K-30), and now the K-3 that can overexpose. I have Highlight Compensation set to Auto at all times; it only kicks in when fairly severe overexposure is sensed (and never kicks in too soon). Even with HC, I often use -0.3 EV compensation, and sometimes use -0.7 EV in extreme conditions. Personally, I hate seeing any blowout, and because I use a RAW converter that deals especially well with shadow noise (C1 v8) the marginal increase in shadow noise is not a major concern to me. Your preference may differ.

Third, with RAW shooting on the K-3 you shouldn't over-think the exposure compensation situation. Obviously, you cannot regain image lost to overexposure. However, the K-3 is proven to be nearly ISO-less, so the data loss from underexposure is quite marginal. In other words, if you happen to expose a scene at 100 ISO that would have been properly exposed at 800 ISO (off by a full three stops), a good RAW converter will bring up the exposure to nearly match the quality of the correct exposure and the noise profile will be surprisingly similar. With this in mind, consider using the TAv setting to allow floating ISO for most shooting situations, especially if lighting conditions are variable.
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