exposure value question ?
Apr 5, 2013 06:19:16 #
georgevedwards wrote:
Wait a minute, wasn't it just established that you can't use the EV button when in Manual?
this was taken from the Nikon web page, hope it helps. by the way Exposure Compensation and Exposure Value (EV) are not the same. Exposure Compensation is set using EV, i.e.. +1 EV or -1EV, etc. Hope this helps.
Apr 5, 2013 06:28:55 #
I THINK that Mark Wallace answers your question here:
Starting at 2:52
http://www.youtube.com/watch?v=UU7rF2RcNsQ#t=02m52s
Starting at 2:52
http://www.youtube.com/watch?v=UU7rF2RcNsQ#t=02m52s
Apr 5, 2013 06:32:58 #
Let's see.
Back before the digital sensor when film was king, we had to meter the light on the subject, adjust our camera shutter speed, set our aperture, select a fim speed (ASA or ISO) and then make the exposure. The film was manufactured with sensativity variables such as ASA 25, 100, 200, 400, etc. The more sensative the film the more apparent grain became. I think it must be obvious that the sensor in the digital camera and it's sensativity is adjusted electronically to the ISO setting you or the camera select. In the Auto mode the camera selects the Speed, aperature, and ISO value based on the light received.
Back before the digital sensor when film was king, we had to meter the light on the subject, adjust our camera shutter speed, set our aperture, select a fim speed (ASA or ISO) and then make the exposure. The film was manufactured with sensativity variables such as ASA 25, 100, 200, 400, etc. The more sensative the film the more apparent grain became. I think it must be obvious that the sensor in the digital camera and it's sensativity is adjusted electronically to the ISO setting you or the camera select. In the Auto mode the camera selects the Speed, aperature, and ISO value based on the light received.
Apr 5, 2013 06:37:17 #
Apr 5, 2013 07:04:35 #
I just did a test shot using the D3 mode set on P. First shot was at F3.2 @ 1/40th. Dialed in +1 EV second shot was at F2.8 @ 1/30th.
Apr 5, 2013 07:33:39 #
rpavich wrote:
But joeb didnt' answer the question.
The question was:
"When in auto modes and you dial in +EV or -EV in the camera...which of the 3 exposure variables is it modifying to get the different EV value"?
The question was:
"When in auto modes and you dial in +EV or -EV in the camera...which of the 3 exposure variables is it modifying to get the different EV value"?
It depends on whether you are shooting full auto (camera may adjust any or all of ISO, aperture or shutter speed), or whether you have locked one of these settings (the camera will adjust either or both of the other two). If you have locked two of them, only the remaining setting will be adjusted by the camera.
You can check the image information in the display to see which one(s) got changed for that specific shot.
Of course, on full manual (ISO not set to Auto), there is no EV adjustment since you have locked all three values.
Apr 5, 2013 07:40:21 #
billybaseball wrote:
... Changing the exposure compensation changes how the camera processes the raw image into a jpg, it does not change your settings. ....
Sorry, but this is not correct. Adjusting EV affects the RAW image.
It changes one or more of the three values (ISO, aperture or shutter speed). Otherwise you could use EV adjustments for full manual (without Auto ISO), which you cannot.
Apr 5, 2013 07:59:39 #
An EV value represents a certain shutter speed/aperture combination. Older 500 c/m Hasselblads had lenses with EV values on the lenses. Once you determined your exposure you could just alter both shutter speed and aperature by turning the lens ring to give the aperture (and depth of field) needed/desires or alternatively, until you had the desired shutter speed.
Remember the hassys had in the lens shutters.
Remember the hassys had in the lens shutters.
Apr 5, 2013 08:32:26 #
rpavich wrote:
But joeb didnt' answer the question.
The question was:
"When in auto modes and you dial in +EV or -EV in the camera...which of the 3 exposure variables is it modifying to get the different EV value"?
The question was:
"When in auto modes and you dial in +EV or -EV in the camera...which of the 3 exposure variables is it modifying to get the different EV value"?
It depends on the mode.
Assuming you are not using auto ISO...
If you are in aperture priority (and so you have specified the aperture) exposure compensation will change the shutter speed.
If you are in shutter priority, it will change the aperture.
P mode is a bit different. It has (for a given focal length) a set of shutter/aperture combinations that it uses as the EV increases changing one then the other to keep them 'balanced' so exposure compensation just moves this up or down the list - see this image: http://www.mir.com.my/rb/photography/hardwares/classics/eos/EOS-1n/Exposures/PGRM_chart.gif
or read this: http://www.mir.com.my/rb/photography/hardwares/classics/eos/EOS-1n/Exposures/
Using auto iso adds a third possible thing to change but the overall idea is the same
Apr 5, 2013 09:04:42 #
BobHartung wrote:
An EV value represents a certain shutter speed/aperture combination. ....
That is correct - EV is just the shutter speed/aperture combination and it is independent of ISO. But with digital, Auto ISO adds another variable that the camera can adjust.
But all of this begs the question: Why change the EV? The answer is simple - because the camera would otherwise automatically calculate the wrong exposure. Maybe the scene is backlit or maybe you want a high-key or low-key photograph and the camera is trying to produce an average exposure or is spot metering the wrong place.
Using a +/-EV adjustment may be a quick way to address these problems but it only gets you closer, it does not solve the problem.
The ultimate solution is to go full manual (including picking a specific ISO), using the monitor to view the result and the histogram to check the distribution of tonality.
Also, there may be no alternative to bracketing, allowing shutter speed or aperture to vary and then checking the result after the images are on the computer.
Apr 5, 2013 09:06:04 #
Searcher wrote:
I have just taken 5 shots Manual exposure, 1/80th ... (show quote)
I'm not quite sure if I understand what you did, but in Manual mode, each time you increase the EC +1 (one full stop), you're decreasing the shutter speed by one full stop - increasing the exposure time.
Apr 5, 2013 09:10:07 #
mfeveland wrote:
I'm not quite sure if I understand what you did, but in Manual mode, each time you increase the EC +1 (one full stop), you're decreasing the shutter speed by one full stop - increasing the exposure time.
I suspect EV control does not work in manual mode. It will only work in Auto mode. Just an idea from what you did and the results.
Apr 5, 2013 09:14:38 #
Shutter speed controls light exposure and aperture controls amount of light to reach subject......
Apr 5, 2013 09:25:11 #
chaprick wrote:
I suspect EV control does not work in manual mode. It will only work in Auto mode. Just an idea from what you did and the results.
Correct. EV and EC are two different animals. I was talking about EC.
Apr 5, 2013 09:34:17 #
JoeB wrote:
If you decrease your shutter speed by one stop, yo... (show quote)
Excellent response but it deals with the manual setting. I believe he is talking about priority modes so if you're in Av aperture priority then EC (exposure compensation) will adjust the shutter speed and if in Tv Time or shutter priority then the EC will adjust the aperture. Now some cameras may, if required, also change the ISO when all other options have been exhausted.
If you're in program or auto modes then all bets are off. It's up to you to watch and see what the camera does. But as we all know, manual is the best for controlling EV (exposure value) results.
:thumbup:
If you want to reply, then register here. Registration is free and your account is created instantly, so you can post right away.