I´ve been wondering for a while now with this problem
If I set my d700 to aperture (as I almost always is set) sometimes there are HUGE differences in two or more images while shooting a slow or fast burst (CL or CH)
At first I thought that it was me. then I started being more careful, then while reviewing some images a few moments ago, I found these two shots..
both shots are with the same settings, the same everything, but for two things, first, the focal length is a slight wider in the slower, thus brighter one shot at 18mm and the first one shot around 30 seconds earlier was shot at 24mm
why does the metering unit takes a so wide range when the metering is set to spot and the spot it is "looking" at is not changing that much? (at least to my eyes)
Sun 03-Jul-11 06:58 AM | edited Sun 03-Jul-11 06:59 AM by Baaker
Are you sure that you don't have your bracketing on? I don't think that spot metering is possibly best for burst mode. Obviously using spot you have to be extra careful when using it. One more thing... why would you use burst on this type of image? It isn't motor sports or something that is fast moving. If you think that using burst to "nail" the shot is best then I think a better technique would help
I am sure there is no bracketing on. As for the spot meter, I usually shot it like this in my kids school as all the background is white and the sun is really harsh, so it usually is best like this, but I am open to improve my technique (it does need improving) as for the burst mode, I left it in that mode from a day before while shooting my kids at the park in a swing, so I needed the speed, forgot to change that, but left it when I noticed the swings in shutter speeds.. will try and shoot less and more accurate next time. thanks
The EXIF data for these two shots shows that the camera was set to manual mode, not aperture. The underexposed shot was at 1/3200 second at f/11, while the properly exposed one was 1/4000 at f/5. With the camera set to manual, you apparently somehow inadvertently changed the aperture between exposures.
John "One should photograph objects not only for what they are but for what else they are." -- Minor White
John you are right... that is when I noticed the change... I am posting two more images with the same problem... And if I remember correctly, what I did wrong was not look at the program settings in the ones previously posted.
back to my problem, why does one image changes so much from the previous in aperture mode, spot metering, same iso, same aperture, same subject, same lighting?? what I can only see in difference is that the image in viewnx does present a focus point in the second image and the first image has no focus point, I think that the spot metering, based on the focus point, meter correctly, but if no focus point shows up, then the metering is off... can this be a bug in my camera??
I have checked the images and the have all the exif data on them...
Mon 04-Jul-11 11:31 AM | edited Mon 04-Jul-11 11:32 AM by jpFoto
I couldn't see the EXIF data in NX2 or Opanda, but as Baaker had suggested in an earlier post, are you sure that you don't have bracketing on. Press the function button and if "0 F" is not show on the top LCD, it is on. Also, the +- light would be blinking in the viewfinder if it's on.
I encounter this all the time in people and landscape photography, film or digital, F5T, D70 or D700. In spot reading, placing the spot on a light (white blouse) area will give a darker rendition to the overall scene while placing the spot over a gray (gray skirt) area will give a brighter overall scene. This works for aperture, shutter, program and manual metering. Nikon's NX and NX2 software can show you where the spot metering sensor was located for each image.
"Great things are not done by impulse but by a series of small things brought together." Vincent Van Gogh
For your consideration (and from my experience) in you gallery album, "Adagio Cancun" two images which caught my attention were DSC2353 and DSC2195. I suggest that when you have an opportunity to do images like these again, that you spot meter the performers' faces, then use center weighted metering. The results will be different but not altogether bad. This will be another way to illustrate how the various metering modes can help set the "mood" of a scene.
"Great things are not done by impulse but by a series of small things brought together." Vincent Van Gogh
I was going through the same line of thought. the Thing is in my NX2, either View or Capture, the focus point will NOT always show...
when the Focus Point does not show, is when the differences are greater.. as I said before, could this be aglicht in my camera software?? I had updated to the lates version, but this was visible to me, after the update.
I am sure the spot area is small, and that if the color within the spot area changes dramatically, so will the exposure, but when there is no focus point to review this?
As for the metering, I think I wll have to change my metering habits, I was used to spot, as it allows me a better handling of the exposure the camera will "get".
I agree with you, and your comment makes me sure I was not all that wrong. Now that I am sure that a little change in the color within the AF point will make the exposure change a lot, the question that remains is why do I not have focus points brackets in all my images in viewnx2 and capture nx2...
will these lack of focus point brackest mean the camera as no fixed af point or is it just the software not being able to place it in the image information??
I believe the later to be true, meaning I have to do one of two things... 1.-be very careful when metering with spot 2.-use center weighted metering to avoid this problem, but this will give new "problems" but it only takes getting used to.. right??
>So regardless of the focus point in the software, the camera >will always choose the spot selected for metering right??
When using Spot Metering, the meter will assess the brightness of a 4mm diameter circular area centred on the focus point that you selected. If you set the camera to Auto-area AF, Spot Metering will always use the central focus point.
One other thought: spot metering is VERY selective. If the focus spot is on one of the white blouses versus the dark skirts or trousers, there will be at least 2+ stops difference in the exposure. Your lighting is very even and I'd be inclined to use 3D Matrix metering here -- averaging the entire scene. Spot metering can be like a computer -- it will calculate the correct solution, assuming you make the proper inputs. It is NOT inherently more precise or correct.
this gets me to a different question, my technique is not good...
blunt and simple...
here is the thing, you´ve seen the images, the background walls are white, the floor is light concrete, looks like white though, there is a big patch of green (grass) at the end of the court, but they usually are in the concrete, If I use 3d matrix, then the whole images goes underexposed by at least 2 stops and the faces turn almost black, trying to recover that in capture is a nightmare and it never gives good results.
there must be something I am doing bad
I´ve answered the original question, do my camera is skewed while shooting several frames in burst? answer NO, I am doing it wrong.
the next question that arose from all of this is what I´ve came up with in this last post, I am doing it wrong...
but how to correct? I will try and do different things in the near future, any ideas?
With scenes such as this (the young dancer) centered weighted metering might be the better choice. At times I have set my center-weighting to 6, 8, 10 or 12mm for the D70 and 8, 12, 15 or 20mm for the D700. Selecting the combination of settings for metering takes time and practice using different lenses to learn the finer points of just what results you can achieve with different settings. I hope our various points of view are helpful.
"Great things are not done by impulse but by a series of small things brought together." Vincent Van Gogh
Titan you are correct. I will try and use both matrix and center weighted, its just that I will have to go back to the school yard and ask for permission to shoot one morning and find out what´s the best choice with no pressure coming from an event like the one in the images. Right now after 3 years of being around all my kids school-mates I´ve turned out to be the "un-official" tog for the kids and parents, but it makes me even more aware of images not turning out as I want them, and I´ve become so picky about my images that very few images are good enough for me..
Humberto -- Your technique is not a problem -- you have a tough lighting situation here, in which there is so much white or very light area that it is dominating your meter. This is frankly a strong argument in favor of "chimping:" shooting and looking at the results, biasing the exposure with the +/- button and looking again. This is a beauty of digital photography. You don't have to wait for the film to be developed to see how things turned out.
So as the situation is being set up, shoot some samples. Check, and then figure out how you must +/- your exposure settings to get the results you want. There may not be an exposure that captures detail in both the brightest areas and darkest areas. But this is where your decision enters: what is MOST important? In this case, I believe faces are. Look at your best results and see if you can discern why they are the best.
You may want to be using your aperture preferred metering and getting the correct exposure determined, and then transferring that to a manual setting so that wherever you point your camera, the camera is exposing for the faces, or whatever you have decided is most important.
A final caution: if you have biased your meter with the +/- button to cause it to over or under expose, you need to be mindful of restoring the camera to your basic settings when you are done so they are not sitting there waiting to ambush you next time! And put the metering back to aperture preferred. In other words, undo what you had to do for the best results in THIS situation!
This has been an exposure discussion with a fire hose! You may want to look at a book on exposure for added discussion and ideas. Today's modern digital cameras are astoundingly capable. But they are in fact computers that take pictures. And like most computers, they will "crunch" whatever inputs you make, whether they are right or not! Your current questioning and introspection are going to make you a superb photographer. We tend to learn more from our mistakes than successes.
Email me if you have specific questions or images to examine. I am retired and have some time. Of course, all of your Nikonian colleagues are superb resources too. And finally, I was told a long time ago, that when you get super results, share them ... and hide the mistakes!
Thank you and everyone else for so much information shared in the previous days.
I know it is a tough situation but this is where a great tog is separated from the rest...So this is why I keep pushing myself. I know if I make a difference in my photography I will learn and have more correct info to input into myself and my machine (aka d700)
I really appreciate everyones comments and I will pinch back later to post some images when the kids come back to school after summer break.
I have posted some new images to my gallery, please take a look and comment...
I have found the spot metering a NIGHTMARE. It feels totally unreliable.I am not convinced it is about my technique but rather think the camera metering is inconsistent. So many crucial shots (i.e. a bride walking down the aisle) are missed because the spot metering is unreliable. Relying on the +/- means precious time wasted and the moment passing. When it works it is great but the not knowing is so frustrating.
I would be very grateful to know if anyone else is experiencing this as a fault rather than about technique....
Tue 12-Jul-11 07:36 AM | edited Tue 12-Jul-11 07:37 AM by briantilley
Welcome to Nikonians, John
It's always possible that an individual camera has a fault with its Spot Meter, but we see more problems here that are due to people not being familiar with how Spot Metering actually works...
The Spot Meter in any Nikon (and, I'm sure, other brands as well) will measure the brightness of the part of the subject under the Spot - depending on other settings, it will generally use the area surrounding the AF point that's in use.
The Meter will assess the brightness of this area, and select an exposure value that will render it as mid-gray in the resulting image. If you were pointing the Spot at a white subject, it will come out grey - significantly under-exposed, and if you were pointing it at a dark subject, it will be over-exposed and still grey.
For Spot Metering to give you the result you want without using exposure compensation, the Spot must be pointed at a part of the subject that has a mid tone.
John it has happened, the spot is not the best, but as everyone here pointed out, the thing is you have to really understand what the metering system is doing. The spot metering is really measuring a very small space in the whole image, and I have found out the hard way, that the slightest movement will make the measurement go all the way around and get over or under exposed images, and the thing is not the camera (although i still have some doubts and am looking into two years of images that were shot spot metered to rpove my point or find out what in the world really happened) as much as the one holding the camera if it is a hand held shot, as I imagine is your case in a wedding.
I would suggest going to center weighted metering that takes into account a bigger area (user definable by the way) around the spot where the AF point is being considered by the camera.
I really don´t got to the 3d matrix metering as I am not that familiar and involved in it yet, but the day will come that I will accpet that metering mode for certain situations.
>I would suggest going to center weighted metering that takes >into account a bigger area (user definable by the way) around >the spot where the AF point is being considered by the >camera.
That's not quite true. Centre-weighted Metering gives more weight to the part of the subject that lies within a circle of user-definable diameter in the centre of the frame. Unlike Spot Metering, this metered circle does not move with the AF point that is chosen.
Thanks for these thoughts. I feel some relief as having made the step up to professional gear I was hoping to be able to rely 100% on it doing the business. When it works spot metering is such a great asset and the inconsistency was one of the reasons I upgraded from a D80 - I'd assumed trouble free metering would be included in the price tag.
I will try the centre weighted as an option as I usually use the spot metering centre spot anyway (if that makes sense). Thanks again for the comments and relief that I don't need to go down the avenue of thinking I need repairs to the camera.... (out of interest I wonder how Canon compares with it's spot metering...)
This might be taken as harping on a bit but having worked on a few images yesterday where the spot metering "let me down" I cannot see how it could have been to do with what has been explained on here. The area that was in focus (i.e. where the spot meter was metering from) AND the surrounding area was all one colour - so therefore not a case of the spot metering on a slightly different part than I realised and giving a very different meter calculation.
There is some consistency in the problem in so much as it "fails" me most when I focus on a badly lit face with a lot of back light behind. Unless I am misunderstanding the (much appreciated) comments above therefore this points to something different...
Without seeing an example image it's difficult to comment further. What tone (degree of light/dark) was the area that you metered? Unless you used compensation, with spot metering it's going to come out as a mid tone, whether it was actually bright, dark, or somewhere in between.
Hi...ok two images posted in my gallery. Slightly different to the discussion above in so much as the successfully lit image was shot using spot whereas the dark underexposed images was shot using centre weighted.
The point remains though that what should be similar exposures are totally different. The focus is on target which presumably is evidence that of where the metering took place....am I more justified in thinking I am being let down by my camera? Thoughts appreciated.... (excuse the slightly grumpy looking wife by the way - she's had a long day at work!!)
>The point remains though that what should be similar exposures >are totally different. The focus is on target which presumably >is evidence that of where the metering took place....am I more >justified in thinking I am being let down by my camera?
No, you're not.
The image shown (a backlit subject) is exactly the type of scene where you should expect Spot and CW metering to give quite different results. The Spot Metered image has successfully recorded the skin as a mid tone, whilst the CW Metered image has been influenced by the bright area just above your wife's head.
TOtally agree with Brian, the image begs for spot and either on her face or on her shirt to give her a well lighted exposure.
the problem is when you get two images with spot metering and they are quite different
and please forgive me for going back to almost the same spot as where we started this thread, but I need to really understand why the differences...
I found the images I was looking for.. here they are...
the first is 63 hundreds of a second earlier that the second one the first has a 1/160 and shutter f/3.5 the second has a 1/80 and shutter f/3.5 both are spot metering, aperture priority and ISO 400 the images are basically the same and the spot is in the SAME place in both images and assuming that the spot area is as small as I think it is, the metered area is the same... (this is the important part, is the spot area as small as i think?)
That's difficult to say without knowing where your focus point was. The image has recorded the wall in the centre background as a mid tone, so I'd guess your focus point was on that. If so, that is again just what should be expected.
both images have both the exact configuration, nothing was changed, in fact I was shooting 2 images in a row (no bracketing is not on, and yes I dont need to shoot bursts, but two thing go in this, one I LOVE the sound of the camera clicking and two, I´ve been havind this issue for a while so...) In fact, the difference between each image is 63 hundreds of a second...
so I was not able to change any settings between each image.
as for the spot, well autofocus was dead on on his nose, if you open the image with view nx, and select the focus point "brackets" to light with images, the AF point is centered and dead on the guys face, in fact it is over the moustache and nose, in the brighter one, the AFpoint is a littel bit higher so there is less moustache to expose and more skin
I believe that would probably be the difference...
but that is making the spot VEEEERRRRYYYYY sensitive...
it is a minuscule difference, is it really this sensitive??
Brian, can I post a selection of hte view nx display in here? and if so, how can I cpoy it from screen? annottate will do?
When you have an image with a strong difference in brightness over a small area - like in this case the bright peak and the dark shadow under it - including a bit more of the bright area could easily result in the 1-stop difference in exposure.
I guess we're only going to get to the bottom of this if you shoot examples where the area of the spot (1/9th of the frame width, remember) covers a solid and continuous tone. Better still, shoot a plain wall filling the whole frame. If successive shots of such an target have different exposures, then something is wrong.
>I have found the spot metering a NIGHTMARE. It feels totally >unreliable.I am not convinced it is about my technique but >rather think the camera metering is inconsistent. So many >crucial shots (i.e. a bride walking down the aisle) are missed >because the spot metering is unreliable. Relying on the +/- >means precious time wasted and the moment passing. When it >works it is great but the not knowing is so frustrating. > >I would be very grateful to know if anyone else is >experiencing this as a fault rather than about technique....=
Not sure if you were using flash for the bride. It is my understanding that with flash in CLS mode the camera defaults to some kind of average area exposure to calculate the flash exposure even if you have spot metering set. I assume the ambient exposure still uses the spot metering however.
I reckon I have got some fresh insight!!! The biggest problem seems to come when there is strong back light. I have been super aware of the diameters and potential to be catching other material in my metering area. But sometimes still get the same problem. I think the strong light streams into the meter and confuses it.
For example when shooting into the sun the other day using spot - there was lots of area around the face that I was focusing on (i.e. the metering wasn't catching something that I hadn't noticed) but the image was hugely underexposed. Anyone agree with this perspective???
Ok, i will try to explain according to what I have learned from this thread (Brian, I know you will eventually read this, pleas do "grade" my thread lessons)...
the spot meter is a very small area, 1/9th the size of the sensor and as far as I know it is round (not sure)
This spot area will measure the amount of brightness coming from the objective you are measuring, therefore if what you are metering is smaller than the spot, the camera will average all the information from what comes "into the spot" (what you are measuring and areas around it, either bright or "dull"), if what you are measuring is bigger than the spot you are metering, then the camera will measure as a same brightness(everything within the spot) and you will have your exposure values according to the same spot.
the thing is that the spot is VERY sensitive and a small and I mean very small change in brightness conditions will make for a huge change in the exposure in the camera.
if I did not explained myself please do tell me and I will try and change my words...