Sun 21-Oct-12 03:29 AM | edited Sun 21-Oct-12 01:14 PM by RRRoger
Today I tried to "Dial In" our D600 better. We went on a WalkAbout in Montery and to the piers. I was trying different Picture Control settings.
When I got home, I uploaded the Large Fine JPEGs that I shot with Quality Priority. To my surprise the differences in images at different Picture Control setting was minor compared to Gain Control. Evidently it is in Automatic mode. What I noticed in the EXIF properties was that when it was normal (no gain) the pictures were all very good in every way, but in low gain they were slightly blown out and when in high gain they were almost completely washed out. How do I turn off "Gain Control"?
>Also, like Brian, I'm curious to know about this "gain >control" of which you speak.
It's not something we have direct control over. It's one of the standard tags in the Camera section of the EXIF data. I think it's related to ISO setting (in Nikon cameras) but am happy to be corrected on that. From the limited research I've done, my D300s has 'None' at ISO 200, and 'Low Gain Up' at ISO 800.
Sun 21-Oct-12 11:11 AM | edited Sun 21-Oct-12 11:16 AM by RRRoger
Thank you all for jumping right in here. I appreciate the helpfulness of Nikonians.
I am opening the JPEGs in ACDsee. Yes it does seem to be a metering problem. I have been using Spot metering for over twelve years without blowing out more than 1 in 100 shots. 1. Perhaps the D600 is more sensitive? 2. Perhaps I should switch to Matrix for today's MotoCross Event? My wife will be using this camera and she tends to get a lot of back focus due to not recomposing each shot as a new Rider goes by. She will just sit there in a daze while holding the AF-ON (AE-L/AF-L) button down with the camera in AF-C.
>Do you have auto iso on? > >If you do and you don't normally use it, the this might >explain the unexpected brightness of your shots<Quote<<<
I normally use Auto ISO 6400 for stills and Manual settings for Video.
Today we shot the D600 in Dynamic 9 point matrix mode, and the D800 in single spot AF-C.
Again each blown out shot had "High Gain". They ranged generally from 400 ISO up to 1600. But I also had some Higher ISO pictures that were not blown out.
I took over 4,000 shots in 6 hours and cannot imagine using manual settings for ISO as I ranged from 100-1600 and had no time to adjust each shot. The Event was MotoCross so I wanted to keep my shutter speed up and aperture low.
My customers expect many shots of each Rider. Mostly they would rather buy a memory shot than an Art Object. But I want to provide the very best I can.
>Are you saying you are using similar settings as on a >previous camera and getting significantly different results?<Quote<<<
My D600 does seem to be more prone to blowing out the images with the same settings. The sensor, AF, and metering are different, so I would expect different results, but the jury is out on that.
I would like to turn off "Gain Control" on all my cameras or whatever is over compensating. Looking back, I think even the black car would look better if the entire picture was darker (less bright). This is not something I can do in post processing. The scene as I saw it thru the lens would be much preferred.
>I would like to turn off "Gain Control" on all my >cameras or whatever is over compensating.
There is no "gain control" to turn off.
The only exposure variables are still ISO, shutter speed and aperture - as Chris explained above, the words you are seeing are likely the software's interpretation of your camera's ISO setting as recorded in the EXIF data.
I think the learning point is that spot metering a black object against a bright background (or a light object against a dark background) will not deliver an accurate overall exposure.
>>I would like to turn off "Gain Control" on all >my >>cameras or whatever is over compensating. > >There is no "gain control" to turn off. > >The only exposure variables are still ISO, shutter speed and >aperture - as Chris explained above, the words you are seeing >are likely the software's interpretation of your camera's ISO >setting as recorded in the EXIF data. > >I think the learning point is that spot metering a black >object against a bright background (or a light object against >a dark background) will not deliver an accurate overall >exposure.
Brian, as you pointed out to me, it is possible to increase the exposure compensation accidentily by rotating only the command dial -- without even pressing the exposure compensation button. (p225, Manual). Most insidiously, if you set Easy Compensation ON (B3) the altered setting is not reset when you turn the camera off. Trust me! It's possible to leave the house with +2EV set for all your wondrous images from your glorious outing.
Hi Roger, Are you using SPOT metering for all the images that appear to be overexposed, the brightness of the scene will not be considered when the camera rightly tries to expose the spot the metering sensor is over to a mid 18%. A black car to be exposed a middle grey is going to be boosted a couple stops over optimum exposure that would have left the black car black. When shooting a black subject, adjusting exposure compensation to a negative value will darken it closer to what your eye sees. In this case the whole scene is very strongly backlit. If Matrix metering is used, the whole scene is considered in the exposure calculation which would have rendered the black car much darker. The only hitch is that the focus sensor sets a bias in Matrix to consider the exposure of the subject under the current active focal point. That means dialing in a little negative EC. to allow the strong back light to expose normally, and the black car looking black. This is a tough scene for spot and spot is best used when a narrow field of view is used, say the black car filling the frame. Getting proper exposure when there are extremes of high and low tones in a scene sometimes requires imagining what the camera sees and tricking it into seeing what you see. Wedding photographers always wrestle with this since they need the wedding dress, usually bright white to look white and the grooms suit to look really black. That means either tricking the camera or focusing on something neutral between the two extremes and locking exposure to refocus, or focus on something on the same focal plane that is mid tone. Stan St Petersburg Russia
Gain Control EXIF properties do seem to relate to ISO. Below 400 = none 400 to 800 = low above 800 = high
Apparently, Auto ISO is overcompensating for low light to much of the time. It is worst with the D600 than any camera I've used. Switching from single spot to (matrix) pattern cut the problem in half but it is still there.
>Apparently, Auto ISO is overcompensating for low light to much >of the time.
Auto ISO does not "compensate". With Auto ISO on, you will still have the same exposure value - just with a different combination of aperture, shutter speed and ISO than you would have had with it turned off.
I really think you are barking up the wrong tree here.
>>Apparently, Auto ISO is overcompensating for low light to >much >>of the time. > >Auto ISO does not "compensate". With Auto ISO on, >you will still have the same exposure value - just with a >different combination of aperture, shutter speed and ISO than >you would have had with it turned off. > >I really think you are barking up the wrong tree here.
Yesterday I was shooting my D800 in Spot metering mode because I like the control it gives me. I just set my wife's D600 to "Auto" because she can not seem to get the little red square on a moving object even in matrix. Is this a good idea or should I just give up and go to some program or (Sports) scene mode for her? Her good pictures are very good but there are just too many deletes.
I notice in the three following photos taken seconds apart with my D800 that the Rider with the white larger White helmet and black jacket is more overexposed (ISO 1250). I think the focus point was the top part of the helmet.
I think the 8mm square fit inside the dark goggles of the other Rider with red shirt. The overall picture is much more acceptable (ISO 500).
And then there was the Rider with black helmet with ISO (360)no gain. Nearly all photos taken with "no gain" were properly exposed.
If the spotmeter was on the black jacket in the top photo, the camera worked correctly because it rendered it as a middle grey. Ditto was the black car in the very first photo. You only get good control with a spotmeter if you're pointing it appropriate subjects or adjusting it accordingly. Matrix is a better choice if you're not comfortable with spot metering.
I think this so-called "gain control" is a bogus, irrelevant issue. Appears to be something outside the control of the photographer, and the EXIF data relating to "gain" is confusing the real issues. I don't pretend to know with certainty what the real issue is, but I suspect it's related to finding optimal exposure settings and corresponding technique.
Spot metering is fine if you have time to identify and zero in on a *mid-tone* part of the subject. Otherwise, it's a ####shoot. For these kinds of subjects, I think center or matrix might be a better choice.
Another thought--if this is fairly consistent daylight lighting, why not find a correct exposure for the *scene* illumination, dial it in manually, and stick with it?
> >Another thought--if this is fairly consistent daylight >lighting, why not find a correct exposure for the *scene* >illumination, dial it in manually, and stick with it? <Quote<<<
That might work for my wife who will sit in one spot and take nearly the same shot of each Rider as they pass her chair. But even then the track is 15 or more foot wide and different colored Bikes and Riders come by on different lines. Plus with her timing the Riders might be 60 ft closer or further from her.
Those 4 shots I took were from the same spot within seconds of each other. The Auto ISO ranged from 280, 360, 500, and 1250. I often cover two or more jumps and a curve at the same time.
I also move my feet between shots as many as 6 times in one Moto as the Riders lap the track.
I took 113 shots of only 7 Riders in 8 minutes and one dropped out. When there are 27 Riders in a Moto, I take a lot more. This leaves me very little time to change settings. It is usually done while walking up to 400 yards to the next spot, or during some kind of break. I am actually surprised my keeper rate is so much better than my wife's. If I did it her way the Riders would have 5 nearly identical pictures to choose from instead of >10 different ones, and I would be selling single photos instead of packages.
I repeat, these guys are not willing to pay $50 for a single 5x7. Now days, many bring DSLRs of their own. But the biggest threat to my sales is the cell phone. It "captures the moment" and they can email or post it almost immediately.
They are after memories not art objects and have bought photos much worst than these. It is mostly me that wants to improve the quality by avoiding blown out pictures. I do not like pictures like the one with the black jacket.
>Matrix metering with Auto ISO should work well for this type of shooting.<Quote<<<
I changed my wife's D600 to matrix and it did help a lot when the Rider was dead center in the viewfinder. Perhaps I should change my D800 as well but keep the smallest area to focus on? A compromise of the Helmet, Jacket and bike should be best as I want all in focus with best lighting effect.
I evidently need to change to 39 point non flash Auto Mode for her but that is a separate issue.
I'm glad it helped. Matrix works pretty well when you have fast action and rapidly changing lighting conditions. Which AF mode to use depends a lot on whether or not your subject will stay aligned with the sensor you've selected or not. I'll often increase the number of active sensors depending on how much "wandering" the subject will do within the frame. Today's AF systems work pretty well at tracking subjects, especially if they have bright, contrasty colors and patterns. Black jackets are pretty tough, though.
Next time out try manual mode. From the shots you posted you do not have rapidly changing light conditions. Full sun is pretty stable lighting unless a cloud comes along. So you have a set amount of light. Meter for that on something that is close to 18 percent grey. Set your shutter and aperature where you want them. Set a specific ISO that corresponds to the light level and shutter speed you want, and leave everything alone for a few minutes while you shoot.
If you have stable light, your black bikes will be black, whites will be white, and colors will be correct.
Your meter wants to turn everything to middle grey. It will tell you that you need a different exposure for a black bike than for a yellow one, but if the light is the same, the exposure shouldn't change.
I realize this is a simplification, but should work well in the context of the pictures you have submitted here.
Patrick, Not sure if the EXIF is available for the pictures I post here but the ISO range in those 4 was 280-1250 and they were all shot within seconds from the same spot. It is not unusual for a wider variation, thus the need for AutoISO.
I agree with those of you that suggest going from spot to matrix metering as the best if only partial solution to my blown out pictures.
Here is a worst case of the day using Matrix on the D600 at AutoISO 900. The subjects look a lot better than the Rider in black jacket. As Stan suggested a negative EV adjustment would have helped a lot too.
Also keep in mind that matrix metering will bias its results based on what the AF sensor is pointed at. If it's pointed at something excessively dark or bright, you can end up with brighter or darker results respectively. As has already been mentioned, if the light is pretty consistent, manual metering can be a good way to avoid variability due to subject brightness and the placement of the AF sensor. When things are varying dramatically, you just have to rely on automation to work, while realizing it's not perfect.
Roger, that is exactly my point. Your ISO should not have changed. Nor should the shutter speed, nor the aperture. Just try my tip the next time you are out in full sun. If you are shooting thousands of shots, take a couple minutes and try this. What's the worst that can happen? A couple blown exposures? Isn't that why you started the thread? Your meter is changing things it should not be changing for the circumstances you described, as seen in the photos you posted.
On a related note, I struggled with metering birds in flight for years, just not willing to trust full-manual settings from metering based off ambient light. Finally I convinced myself to just try it, and there's pretty much no going back. This should work trouble-free as long as lighting is not rapidly changing i.e. sun in and out of clouds or sunrise/sunset.
I don't know if this is applicable or not. I recently switched to the D600 from a Pentax K-5. What I'm noticing is that the D600 seems to have a much smaller spot for spot metering. Might that be the problem? Instead of spot metering, I'm using the center 9 focusing points and getting pretty consistent results.
There may be some confusion here regarding metering area sizes...
The spot meter circle is 4mm, per Nikon, not 8mm, and I do not believe it is adjustable.
The center weighted circle size is adjustable- 8, 12,15, 20mm or entire frame. It is 12mm out of the box.
I think your images are consistent with a ~4mm spot size. I think the EXIF gain is a Red Herring here. If you don't want to use Matrix Metering (which is what I would try to use), you may be better off with a more forgiving 8mm center weight. That is a circle about 1/3 the height of the screen, or about the size of the bike and rider in your samples.
The main disadvantage of center weight is that the center weight circle will not follow the focus point so you will have to use the center focus sensor to make it work the way you might want.
I've seen spot metering do some things I cannot divine (on my D700 and D300, for example, that I mainly shoot now). I just accept that when "blindly" spot metering and shooting fast I lose some images. I only do it when the subject is rapidly moving from a dark, backlit scene to a brightly lit scene, where matrix metering tends not to work (with very backlit subjects) but it seems to get better with each generation of matrix metering.
See pg 226 (Custom Menu b4 - Center Weight Meter Size Setting) and pg 109 (Spot Size) in your D600 manual.