Spot metering & White balance

[stamper]

In another forum it was stated that using spot metering can change white balance which is something that I hadn't read about. If for instance I am using AWB in camera and I am shooting landscapes what I normally do is spot meter for the sky and lock exposure. I then dial in EV 1.7, or similar, and recompose and focus where appropriate. How is this going to affect white balance?

[Rob C]

In another forum it was stated that using spot metering can change white balance which is something that I hadn't read about. If for instance I am using AWB in camera and I am shooting landscapes what I normally do is spot meter for the sky and lock exposure. I then dial in EV 1.7, or similar, and recompose and focus where appropriate. How is this going to affect white balance?

As I'm from the classic age of snappers, I am rather innocent of digital vices. But, as we both use the D700, if you shoot raw, all you ever need do is leave the damn thing set on sunlight. It makes no difference to the NEF files, as I understand it, only to jpegs. I never shoot jpegs so have not noticed any difference there might be.

Using spot seems an awkward way; the matrix is so accurate it makes your ears bleed. Anyway, the spot that's built into cameras has too wide an acceptance angle to be worth much as a spot; I used it a few times with the Nikon F4s but eventually realised that the incident light reading from the Minolta Flash meter was far more accurate, but if you do use the spot feature, then look for what you think looks like a mid-tone (not just grey, mid- anything works exactly the same). Alternatively, if you can find a white, open up by about a stop and a half. That worked perfectly well with film; digi is supposed to be so much better DR-wise that you should be home and dry.

I have never bothered going off Matrix, only trying the others with the D200 and settling for Matrix with that, too.

Rob C

[langier]

After years shooting digital capture with Nikons, I never bother with other than Matrix and confirming with the 21st century light meter called a histogram on the back of the camera for exposures.

As for light-balance, first I shoot raw, second set wb to daylight. If I'm shooting in incandescent or under florescent, I'll change the balance, but this only affects the embedded jpeg "preview" file. Since the histogram can be skewed by the wb, you do need to set the gist of the wb to the condition at hand, even with awb which matches the intent that the camera engineers deem is right for you, not necessarily what you want...

I shoot an average of about 100,000 images per year. Outside, simply setting the balance to "Daylight" has been close-enough for the preview under nearly all conditions. Most images simply need a little tweaking when they are processed. Just shoot and worry about final color balance back in your studio with your calibrated monitors, not out in the field with a less than ideal and uncalibrated and dinky preview under less than ideal lighting conditions.

Bottom line is that the image still must be crafted back in the studio for wb, exposure, etc., unless this is for a newspaper/web under deadline where simply pleasing and close-enough color/exposure is good enough.

[stamper]

Personally I sort out any WB issues in the computer so what I asked is really a non issue for my self. It was however a technical question that I was wondering about. Rob

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Anyway, the spot that's built into cameras has too wide an acceptance angle to be worth much as a spot;

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the spot on the d700 is only 3mm so it isn't wide and it can't be expanded. The centre weight can be expanded and can be used as a wide spot meter. After reading all about how matrix works I decided it wasn't for me. Basing exposure on thousands of images stored in your camera isn't  - imo - photography. If you up the EV by 2.0 what image in the store is applicable? Back to the original question If a 3mm wide spot meter can affect WB then there is a problem? A sunny day and I set WB for daylight to counter the blue cast. I use my spot meter on a light area to expand the dynamic range - Rob you quite rightly pointed out it's worth - and lo and behold if what I read is true the WB changes. That means it isn't worth setting WB in camera. For me not a problem but for the shooters who like to do it in camera it is.

[Rob C]

Personally I sort out any WB issues in the computer so what I asked is really a non issue for my self. It was however a technical question that I was wondering about. Rob

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Anyway, the spot that's built into cameras has too wide an acceptance angle to be worth much as a spot;

Unquote

the spot on the d700 is only 3mm so it isn't wide and it can't be expanded. The centre weight can be expanded and can be used as a wide spot meter. After reading all about how matrix works I decided it wasn't for me. Basing exposure on thousands of images stored in your camera isn't  - imo - photography. If you up the EV by 2.0 what image in the store is applicable? Back to the original question If a 3mm wide spot meter can affect WB then there is a problem? A sunny day and I set WB for daylight to counter the blue cast. I use my spot meter on a light area to expand the dynamic range - Rob you quite rightly pointed out it's worth - and lo and behold if what I read is true the WB changes. That means it isn't worth setting WB in camera. For me not a problem but for the shooters who like to do it in camera it is.

Stamper

A proper spot meter measures around a max. of one degree; measuring three is far form ideal.
Trust me, the Matrix system is not to be read about, only tried! It sure simplifies shooting. I match the needle to the central line and have stopped worrying about the histogram. If I'm doing closeups with the 105mm then yes, I mess around with it to ETR, but in normal practice, no longer.

If one wants to pixel peep, then I'm sure some differences will be discovered; but in reality and off tripod, it matters precious little - I'd rather catch the shot than wank. (I hope there's no connection to be made.)

Rob C

[stamper]

Rob I shot with matrix for years. I then learned about matrix, spot and center weight. Next I discovered that when using matrix that there were about 30,000 images stored on my camera and the camera was making a reference to one of them to give me a "proper" exposure. I don't shoot for a mid grey which I believe matrix is best suited to. I therefore use center weight where the scene is within contrast range or spot where the contrast range exceeds the dynamic range of the camera. I also use EV 2.0 above and below to expose "correctly". Sometimes full manual, mostly aperture priority. Never auto. Auto Iso I use a lot. I am surprised that an "old Pro" like yourself advocating matrix especially when you state you have a fondness for old manual lenses. At the end of the day it is horses for courses?

[Rob C]

Rob I shot with matrix for years. I then learned about matrix, spot and center weight. Next I discovered that when using matrix that there were about 30,000 images stored on my camera and the camera was making a reference to one of them to give me a "proper" exposure. I don't shoot for a mid grey which I believe matrix is best suited to. I therefore use center weight where the scene is within contrast range or spot where the contrast range exceeds the dynamic range of the camera. I also use EV 2.0 above and below to expose "correctly". Sometimes full manual, mostly aperture priority. Never auto. Auto Iso I use a lot. I am surprised that an "old Pro" like yourself advocating matrix especially when you state you have a fondness for old manual lenses. At the end of the day it is horses for courses?

Hi Stamper

I must be missing something here. What have manual lenses to do with Matrix? You watch the needle, move either the diaphragm or use your right thumb to turn the wheel at the back. That's it, millisecs.

I think you are assuming that the 'basis' for the Matrix functioning is somehow less than accurate or is making you less of a snapper. You could extend that to your notion of spot, too, as it's based, supposedly, on an eighteen percent reflectance value, which, I have also read, is not true, that in reality it's based closer to fourteen percent. But that matters not at all: it is just part of a standardized system, based on something that all makers more or less agree upon.

As I said before, in film days (trannies) I used an incident light meter exclusively - Minolta Flash Model 3 or something like that - and prior to that, a series of Weston Masters. Whatever you use, they are all tools designed by someone else, and I don't see it made anyone less a photographer to use them. The photographer part came in when you had understood how to work them, not necessarily why they worked. The same in my view, applies to Matrix, as good a system as I ever found.

In contrast, I've never used variable ISO! Not that I have anything against it, having never used it, but that it simply doesn't enter my mind. I rather keep it simple - suits my mindset.

I note your reasons for using centre-weighted. My F2 Photomic had that and I never used it at all after the first few attempts; the F3 has a similar centre-weighted system too, and though its fair enough for fast, flattish b/w like HP4, I'd never dream of using it for important stuff or transparencies - far too vague. As for spot, with tranny, if you are sitting on the shady side of a mountain and want to shoot the sunny side across the valley, then an incident meter ain't that hot; use the spot and then calculate what your chosen 'mid-tone' really is - how close to a mid-tone is it? -and then adjust your camera to suit where white should sit.

Thank God Matrix relieves you of all that nonsense!

;-)

Rob C

[stamper]

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Hi Stamper

I must be missing something here. What have manual lenses to do with Matrix? You watch the needle, move either the diaphragm or use your right thumb to turn the wheel at the back. That's it, millisecs.

Unquote

Rob as an experienced photographer - far more than me - I thought you would you would have moved further on in photographic terms with respect to using matrix. Spot metering and center weight were what experienced photographers used in the past. As a user of manual lenses it struck me that you would have wanted - and enjoyed - using the methods that had the most user input. If your photography is flagging - which you have stated in the past - then using these methods will give you more enjoyment? I was surprised when you advocated using matrix given your background. I don't think that any of your present day photography has to be hurried as in the past when you worked professionally? Personally using matrix is  - imo - the least best method of metering.  

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I think you are assuming that the 'basis' for the Matrix functioning is somehow less than accurate or is making you less of a snapper.

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I think it is less than accurate. Think about it. Something like 30,000 images stored on my camera. Who chose them and why? Are they all exposed for a mid grey? If so what happens if I have a + 2 EV set on my camera and I am shooting Ben Lomond with snow on the top and choppy waters at the bottom which image in the collection does it choose to set the exposure? Somebody more intelligent and experienced than me can possibly explain it. Are you saying that this method is better than the older methods that were used before. Did your film cameras have access to this? NO.

[Dick Roadnight]

...confirming with the 21st century light meter called a histogram on the back of the camera for exposures.

I have not used a hand-held meter for any digital camera... the histogram (and clipping indicator) is the meter.

[Dick Roadnight]

In contrast, I've never used variable ISO! Not that I have anything against it, having never used it, but that it simply doesn't enter my mind. I rather keep it simple - suits my mindset.
Rob C

I used to always use base ISO, as I thought it would produce the best results, but when hand-holding a long lens for ambient portraiture, where you need f16 for DOF and, at most 1/300th for camera shake, 50 ISO is not an option. I think we need and auto-ISO option, but the camera would need to know is we were hand-holding the camera.

Did you not ever use fast film?

I used to keep fast film in one of my backs, but seldom used it.

[Rob C]

I used to always use base ISO, as I thought it would produce the best results, but when hand-holding a long lens for ambient portraiture, where you need f16 for DOF and, at most 1/300th for camera shake, 50 ISO is not an option. I think we need and auto-ISO option, but the camera would need to know is we were hand-holding the camera.

Did you not ever use fast film?

I used to keep fast film in one of my backs, but seldom used it.

Fast film. I used very few different film types, mostly medium speed.

For the colour calendar stuff it was about 99% Kodachrome 64 Pro, a little Ektachrome 64 came in if the client stipulated 120.

With b/w, in 35mm it was mainly FP3/later FP4 at 125ASA and HP3/later HP4 (never Tri-X) at 320ASA. On 120 I used only two types: Ektachrome 64 and TXP 120 at 320ASA. All the b/w films went through D76 1+1 at the tested standard developments I discovered worked for me.

I seldom uprated filmspeed, because the truth is you can't: all you do is slide the exposure along the scale and lose out at the extreme end because you have had to extend development. Many photographers used to think they were pulling imaginary rabbits out of hats that way, but it's what they wanted to believe and the results were not, then, critically observed for the reality of what they were: crap. Or, if you like, effect. Fortunately, my kind of work never needed extreme handling.

On digital, I'm hardly ever off the base speed; again, I don't need it.

However, to be fair, very fast film was something I was never allowed to use. My clients were not - or their clients were not - able to recognize the Sarah Moon style of 500ASA colour film work for the high art that I think it was, and would have loved to have been able to utilise now and again. Come to think of it, a friend has just shot a house in Ibiza and on display there is a beautiful Sarah Moon from her '72 Pirelli shoot at Malmaison, Paris. The grain is a beauty in itself. I wonder how many pulls from the highly retouched, plastic-looking stuff from the top guns of today will be hanging as art in peoples' homes in 30 year's time...

Rob C

[Dick Roadnight]

With b/w, in 35mm it was mainly FP3/later FP4 at 125ASA and HP3/later HP4 (never Tri-X) at 320ASA. On 120 I used only two types: Ektachrome 64 and TXP 120 at 320ASA. All the b/w films went through D76 1+1 at the tested standard developments I discovered worked for me.
Rob C

Even back in the 60s and 70s I wanted detail, so I used Pan f (50asa) @ 100asa developed in Acutol for chemical sharpening.

When I moved to MF (for more detail) I noticed that 200/400 asa MF was no better than 100 asa 35mm, so I used 100 asa on MF!

[bjanes]

I used to always use base ISO, as I thought it would produce the best results, but when hand-holding a long lens for ambient portraiture, where you need f16 for DOF and, at most 1/300th for camera shake, 50 ISO is not an option. I think we need and auto-ISO option, but the camera would need to know is we were hand-holding the camera.

Depending on what camera you are using, there may not be as much need for auto-ISO as one might think. When you are limited by shutter speed and f/stop considerations, you give as much exposure as possible and then you have to decide about how this exposure should be processed. If you are shooting JPEG, you would raise the ISO for an ETTR exposure. If you are wisely shooting raw, you can raise the ISO on the camera or increase exposure in the raw converter.

With some cameras, such as the Nikon D3s, you would increase the ISO, since this camera has a higher read noise at lower ISOs. As you raise the ISO on this camera there are diminishing returns from higher ISO and the read noise reaches a minimum. If you raise ISO further, you will get a nice looking ETTR histogram on the camera preview, but you are merely limiting highlight read room and it would have been better to have left the ISO setting at a lower value.

Emil Martinec explains this in detail along with how to determine this point of diminishing returns from the DXO DR plots. The D3s is geared for speed, and it is difficult to have a high readout rate and low read noise. If you have a D3x or Phase 1 P65+ with a more leisurely readout rate and good electronics, there is little need to increase the ISO and one can handle the increased exposure entirely in the raw converter.

Bill

[Rob C]

bjanes -this seems to match the subliminal feeling that I have found using the D700. Not that I have used it above base 200ISO other than to see how it worked out, but because even at base ISO, the histograms when working within the NX2 process seem to permit a huge degree of up and down exposure adjustment, almost enough to make any form of accurate exposure at camera level appear pretty pointless if you can avoid blown highlights! However, I can't accept that my obervation can mean what I think that it might, so I continue to try for that matched needle!

Bill - I can't understand what you mean about 200/400 ASA film (on MF) not being better than 100 ASA on 35mm, and so you used100 ASA on 120 format.

The difference is huge. On MF I discovered that FP3 (125 ASA) did not work well with Hasselblad optics; the contrast and 'colour'  was downright ugly with empty mid-tone shadows, and the need for a smaller aperture to compensate for less DoF on the larger format was very real. With the same studio flash units, the only way to get there was faster film - 320ASA-rated TXP. With Ektachrome 64 it was a real problem that needed closer lights and the attendant change in look that gave.

But then, a lot depends where you need to go with it all. Most prints I had to do fitted easily within a 10X12 sheet, and the other extreme, 60ins on 40ins rolls, were for shop and exhibition stands, and there I found 35mm quite useful too, though close encounters of the sniffing kind would reveal the flaws!

Rob C

[Dick Roadnight]

I can't understand what you mean about 200/400 ASA film (on MF) not being better than 100 ASA on 35mm, and so you used100 ASA on 120 format.

The difference is huge. On MF I discovered that FP3 (125 ASA) did not work well with Hasselblad optics; the contrast and 'colour'  was downright ugly with empty mid-tone shadows, and the need for a smaller aperture to compensate for less DoF on the larger format was very real. With the same studio flash units, the only way to get there was faster film - 320ASA-rated TXP. With Ektachrome 64 it was a real problem that needed closer lights and the attendant change in look that gave.
Rob C

Hi, Rob...

Perhaps that is why I used 4 strobes with reflectors/umbrellas, to keep the lighting contrast low... you say that you changed your lighting for the Ektachrome 64.

High speed monochrome was so low-contrast that some people used only one light.

Are you saying that you used wishy-washy film to compensate for the excellence/contrast of your optics?

Pan f was finer grained, nice and contrasty, and I used Acutol, which raised the speed to 100 asa and chemically sharpened the image.

I bought a Sinar to help with the DOF, with a roll film back the format was similar. 66, 69.

[Rob C]

Hi, Rob...

Perhaps that is why I used 4 strobes with reflectors/umbrellas, to keep the lighting contrast low... you say that you changed your lighting for the Ektachrome 64.

High speed monochrome was so low-contrast that some people used only one light.

Are you saying that you used wishy-washy film to compensate for the excellence/contrast of your optics?

Pan f was finer grained, nice and contrasty, and I used Acutol, which raised the speed to 100 asa and chemically sharpened the image.

I bought a Sinar to help with the DOF, with a roll film back the format was similar. 66, 69.

Yes, the change was to bring the light closer, but that darn inverse square law made that difficult in the reality - even a stop of gain was hard fought for...

I used a single 'brolly for most of my studio stuff as illumination for the model; sometimes a kicker at the back to outline her, and often another light to kill the shadow on the colorama roll. I always believed, and still do, that simplicity is key. Otherwise, there'd be more than one Sun. God knew best ;-)

I never found TXP 120 to be an inferior film; as I said, I disliked the finer grained stuff for their look in that format. Pan F and Pan X were something I used in my very first ventures into photography; I soon realised that under 125ASA or so was a waste of time and totally unrealistic for me and what I had to do.

However, that's just my experience; it must have had value in many applications because both remained in production for a very long time.

Rob C