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Thread: SL and exposure problem with the WATE

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    Senior Member Robert Campbell's Avatar
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    SL and exposure problem with the WATE

    I normally use the KISS technique with the kit lens; Aperture priority, Auto focus, Auto ISO, maximum exposure of 1/2f and multi-field metering. Most of the time this works well enough.

    I have to photograph house interiors – I'm house hunting – and like to take a few images to send to family members elsewhere in Europe. I find that estate agents (realtors) can be rather selective in their photos in the brochures or on-line; they mostly use 28mm equivalent lenses. I'm not looking for perfectly exposed, focussed and composed images – there isn't the time for this, rather ones that show the rooms 'warts and all' – and many rooms in the UK and Ireland are really quite small. I'm not concerned about the contrast between inside and outside, I just want to see what the interiors are really like.

    But...using the WATE at 16mm with this set-up doesn't work. As I stop down, not only does the EVF get darker, but the histogram bunches up to the left. I have very generous ISO limits (up to 25,000), noise in these circumstances doesn't worry me. I tried various combinations of maximum shutter speed, but this had little effect. The ISO might rise a bit, but the image was still underexposed.

    I tried centre-weighted metering; the same thing happened, the ISO would rise a bit, but the image was also bunched to the left and underexposed.

    I then tried spot metering, and this works as expected; as I stop down, the ISO rises in parallel, and the images aren't underexposed.

    What's going on? What am I not understanding now?
    Sláinte

    Robert.

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    Re: SL and exposure problem with the WATE

    Hi Robert, it sounds suspiciously like my issue a few weeks ago. Maybe check the helpful answers I got at this link,

    Dave S

    The other option is manual exposure meter and force it to do what you want. IE manual, set aperture and set speed and set ISO.

    http://www.getdpi.com/forum/leica/57...not-right.html
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    Re: SL and exposure problem with the WATE

    Auto ISO refuses to let you have a shutter speed less than 1/2f (if that's what you set) and or an ISO greater than your max setting (I think 1600 is the default -- I use 3200 and others recommend 6400). If you want to stop down too far, it will give you underexposure.

    So keep it simple -- set the highest ISO that you are comfortable with, stay in Aperture mode, choose the aperture you need for depth of field and brace yourself to work at the slower shutter speeds that will result. If you are indoors in reasonable light, and using an aperture like f/5.6 or f/8, this will work. Check the histogram when you half-press the shutter. If it stays centered, you are OK. If it shifts to the left when you half-press, then switch on some more lights, or open up the aperture a bit.

    This is a subject that has gotten a lot of discussion, and there are more detailed posts that you can read on it.

    scott
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    Re: SL and exposure problem with the WATE

    Dave, Scott; thanks for the responses. I'm trying to get some 'snaps' to share with family members while being taken round a house I'm viewing. There isn't time or opportunity to change the lighting.

    My problem seems to be that auto-exposure seems to work OK in spot metering mode, but not in centre-weighted or matrix.

    I didn't record the details of my 'testing', but I'll try to do this tomorrow, and report back.

    - - - Updated - - -

    Quote Originally Posted by DaveS View Post
    Hi Robert, it sounds suspiciously like my issue a few weeks ago. Maybe check the helpful answers I got at this link,

    Dave S

    The other option is manual exposure meter and force it to do what you want. IE manual, set aperture and set speed and set ISO.

    http://www.getdpi.com/forum/leica/57...not-right.html
    Thanks, Dave; I remember the post. I wasn't sure if I had the same problem, or if it was just me. (It usually is.)
    Sláinte

    Robert.

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    Re: SL and exposure problem with the WATE

    Quote Originally Posted by Robert Campbell View Post
    I normally use the KISS technique with the kit lens; Aperture priority, Auto focus, Auto ISO, maximum exposure of 1/2f and multi-field metering. Most of the time this works well enough.

    I have to photograph house interiors – I'm house hunting – and like to take a few images to send to family members elsewhere in Europe. I find that estate agents (realtors) can be rather selective in their photos in the brochures or on-line; they mostly use 28mm equivalent lenses. I'm not looking for perfectly exposed, focussed and composed images – there isn't the time for this, rather ones that show the rooms 'warts and all' – and many rooms in the UK and Ireland are really quite small. I'm not concerned about the contrast between inside and outside, I just want to see what the interiors are really like.

    But...using the WATE at 16mm with this set-up doesn't work. As I stop down, not only does the EVF get darker, but the histogram bunches up to the left. I have very generous ISO limits (up to 25,000), noise in these circumstances doesn't worry me. I tried various combinations of maximum shutter speed, but this had little effect. The ISO might rise a bit, but the image was still underexposed.

    I tried centre-weighted metering; the same thing happened, the ISO would rise a bit, but the image was also bunched to the left and underexposed.

    I then tried spot metering, and this works as expected; as I stop down, the ISO rises in parallel, and the images aren't underexposed.

    What's going on? What am I not understanding now?

    Hi Robert,

    My assumption is that the Multi and Center-weight metering are being fooled by the wide angle ... they are accounting for areas with light that overwhelm the rest of the scene ... like a bright landscape sky overwhelming
    the trees and grass. So in spot metering the meter sees what you want it to see ... no input from those areas that are too bright ... leading to a correct exposure.

    Your best bet may be a grey card with spot metering ... which can help with WB in addition to a more correct exposure.

    Remember that Leica gestalt is manual focus manual meter ... changing slowly but they assume that a this level you will work a bit
    more than the majority of Canikon owners who want 150K scene memory in the multimeter chip mode.

    No way that ISO 25000 cannot give you an appropriate exposure ... so I assume that other factors are in play.

    Whibal makes a series of small pocketable Grey White Black cards that are perfect for this.

    whibal | B&H Photo Video


    Luckily most architectural subjects are static enough to allow you time to do the manual thing.

    Regards,

    Bob
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    Re: SL and exposure problem with the WATE

    Dave, Scott; thanks for the responses. I'm trying to get some 'snaps' to share with family members while being taken round a house I'm viewing. There isn't time or opportunity to change the lighting.

    My problem seems to be that auto-exposure seems to work OK in spot metering mode, but not in centre-weighted or matrix.

    I didn't record the details of my 'testing', but I'll try to do this tomorrow, and report back.

    ...
    This is a fairly typical example of what I'm trying to capture:



    The window is behind me. The grey thing on the wall is an 18% grey card, which I concentrated on for spot metering. There is a colour checker on the box near the centre. (This taken at f4 and multi-field metering). You can see why my temporary lodgings are known as The Hovel. It's a grey, overcast day. I opened this in LR 6.3, and uploaded to Flickr; I made no corrections in LR.

    I used a 6-bit coded WATE at 16 mm; Auto exposure, auto ISO (maximum 25,000), and shutter speed of 1/60. (If I use 1/2f, the shutter speed is 1/30 – 2 x 16 = 30?). The focus is on the junk on the box. This isn't meant to be a creative or artistic view; it's a snap for my convenience, and to send off (with a commentary) to scattered family members. There's neither time nor opportunity to take 'proper' images when you are viewing a house for sale, listening to the estate agent's woffle, and looking for the problems that the owners have tried to conceal (in this country, damp usually).

    Multi-field metering

    f.......................ISO

    4.......................640
    5.6...................1000
    8......................1600
    11.....................2000
    16.....................2500
    22.....................6400

    Centre-weighted metering:

    f........................ISO
    4........................640
    5.6....................1000
    8.......................1600
    11......................2000
    16......................2500
    22......................4000

    Spot metering:

    f.........................ISO
    4.........................500
    5.6.....................1000
    8........................2000
    11......................4000
    16......................8000
    22.....................16000

    As I stop down, neither multi-field nor centre-weighted respond with an appropriate increase in ISO; this is clearly seen as the viewfinder darkening, and the histogram bunches towards the left.

    But with spot metering, the rise in ISO exactly parallels the narrowing aperature; and the exposure at f22 looks much the same as at f4 (there's more noise, obviously).

    I did repeat the 'tests' several times, but always with the same/similar results. I also tried Manual mode, setting the shutter for 1/60; the results were the same. (That is, the ISO at f4 might be 640, or 500; but the progression from baseline is always in the same proportions.)

    So, why doesn't the ISO rise appropriately in multi-field or centre-weighted as it does in spot metering?
    Last edited by Robert Campbell; 25th February 2016 at 07:18.
    Sláinte

    Robert.

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    Re: SL and exposure problem with the WATE

    Quote Originally Posted by docmoore View Post
    Hi Robert,

    My assumption is that the Multi and Center-weight metering are being fooled by the wide angle ... they are accounting for areas with light that overwhelm the rest of the scene ... like a bright landscape sky overwhelming
    the trees and grass. So in spot metering the meter sees what you want it to see ... no input from those areas that are too bright ... leading to a correct exposure.

    Your best bet may be a grey card with spot metering ... which can help with WB in addition to a more correct exposure.

    Remember that Leica gestalt is manual focus manual meter ... changing slowly but they assume that a this level you will work a bit
    more than the majority of Canikon owners who want 150K scene memory in the multimeter chip mode.

    No way that ISO 25000 cannot give you an appropriate exposure ... so I assume that other factors are in play.

    Whibal makes a series of small pocketable Grey White Black cards that are perfect for this.

    whibal | B&H Photo Video


    Luckily most architectural subjects are static enough to allow you time to do the manual thing.

    Regards,

    Bob
    Bob,

    Thanks for your answer. See my test findings, above. I still don't follow why the ISO doesn't appropriately rise in multi-field or centre-weighted metering. Alas, when viewing a house for sale I just don't have the time to take 'proper' photos, just impressions to share.
    Sláinte

    Robert.

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    Re: SL and exposure problem with the WATE

    Robert,

    My only guess is that as you stop down there is enough light over the multi field and center weight due to their
    sample size that the camera "sees" relatively more light than the small spot area measures. And it may be due to
    internal reflection or just the way the WATE refracts light ... or an interaction between the WATE and the adapter for
    the SL.

    However you at least have a way of measuring that approximates correct exposure ... which is why Leica offers
    three different modes ... as some fail in certain instances ... like severe contrasty backlit situations. And it appears
    to be the case here. Would be interesting to see the results on a M240 with the lens.

    Just a guess on my part.

    Confusing to say the least and really points out the utility of the histogram on review.

    I remember shooting early in the morning on a river that ran near the base of a small mountain in Wales ... fog
    rising from the river surface and light just coming over the top of the mountain but not into the river. Without chimping
    the histogram I would have missed every shot. As it was I had to correct about six time to get an appropriate exposure
    with the dynamic range involved ... and a very early Canon 20D.

    Bob
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    Re: SL and exposure problem with the WATE

    Thanks, Bob.

    Using spot metering isn't a problem; I've live histogram turned on, rather than relying on the darkness of the viewfinder.

    I don't have an M240; but if I can, I'll try some other M lenses on the SL tomorrow. (I have another house to view then.)
    Sláinte

    Robert.

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    Re: SL and exposure problem with the WATE

    Quote Originally Posted by Robert Campbell View Post
    Thanks, Bob.

    Using spot metering isn't a problem; I've live histogram turned on, rather than relying on the darkness of the viewfinder.

    I don't have an M240; but if I can, I'll try some other M lenses on the SL tomorrow. (I have another house to view then.)
    Tried this briefly, using a 28mm and a 50 mm lens on the SL; same interior. It's rather brighter today.

    Exactly the same thing; multi-field metering with both lenses gradually underexposes, with the ISO rising a bit though not appropriately as I close the aperture. Using spot metering, the ISO rises arithmetically and the histogram remains unchanged (it does take a moment or two for the exposure and histogram to update as I alter the aperture).

    So what's going on? Have I inadvertently changed some function buried deep in the bowels of the menu system?

    Can anyone replicate this behaviour?
    Sláinte

    Robert.

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    Re: SL and exposure problem with the WATE

    Quote Originally Posted by Robert Campbell View Post
    Tried this briefly, using a 28mm and a 50 mm lens on the SL; same interior. It's rather brighter today.

    Exactly the same thing; multi-field metering with both lenses gradually underexposes, with the ISO rising a bit though not appropriately as I close the aperture. Using spot metering, the ISO rises arithmetically and the histogram remains unchanged (it does take a moment or two for the exposure and histogram to update as I alter the aperture).

    So what's going on? Have I inadvertently changed some function buried deep in the bowels of the menu system?

    Can anyone replicate this behaviour?
    Could have something to do with vignetting and vignetting correction? I mean maybe multimetering at wide f-stop mesures "dark"/vignetted corners and therefore leads to a longer exposure vs spot which measures in the midle only?
    Just a thought.

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    Re: SL and exposure problem with the WATE

    It doesn't matter what lens you're using. I get the same results with all my R lenses. When near the lower limits of the metering range, matrix and cw metering either in A or M mode become unreliable.

    For whatever reason (under-range metering error, etc) the most consistent metering with adapted lenses is achieved with spot metering pattern. The same behavior, or at least not to the same degree, isn't apparent with the VE-SL 24-90mm lens or T lenses. I believe it has some to do with the camera being in full control of the aperture on the dedicated lenses.

    As a practical matter, in this situation I just switch to spot metering and use this workflow:

    - focus
    - meter (AE-L if in A mode)
    - frame
    - make exposure

    FYI: If you have the time, you can check metering accuracy by entering exposure simulation mode (two presses on the FN button). That enables the viewfinder as a visual light meter. With an adapted lens, you can tweak exposure with the lens opening (or shutter speed if in M mode) to get what you want.

    G
    Godfrey - GDGPhoto Flickr Stream
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    Re: SL and exposure problem with the WATE

    Quote Originally Posted by Godfrey View Post
    It doesn't matter what lens you're using. I get the same results with all my R lenses. When near the lower limits of the metering range, matrix and cw metering either in A or M mode become unreliable.

    For whatever reason (under-range metering error, etc) the most consistent metering with adapted lenses is achieved with spot metering pattern. The same behavior, or at least not to the same degree, isn't apparent with the VE-SL 24-90mm lens or T lenses. I believe it has some to do with the camera being in full control of the aperture on the dedicated lenses.

    As a practical matter, in this situation I just switch to spot metering and use this workflow:

    - focus
    - meter (AE-L if in A mode)
    - frame
    - make exposure

    FYI: If you have the time, you can check metering accuracy by entering exposure simulation mode (two presses on the FN button). That enables the viewfinder as a visual light meter. With an adapted lens, you can tweak exposure with the lens opening (or shutter speed if in M mode) to get what you want.

    G
    Thanks, Godfrey.

    I did see your post a couple of weeks ago about a similar problem; I wasn't sure if I had the same difficulty. While I understand what you are saying, I find it difficult to see why the metering works well as spot, but not as matrix or centre weighted. Viewing the house today, in A mode, I used spot; focus with the WATE at 16mm and f8 isn't that critical. Worked pretty well, though trying to take pix of the internal cupboards was a bit challenging. (I don't have a flash).

    (And as an example of how not to market an over-priced house...that's another story.)
    Sláinte

    Robert.

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    Re: SL and exposure problem with the WATE

    Quote Originally Posted by Robert Campbell View Post
    Thanks, Godfrey.

    I did see your post a couple of weeks ago about a similar problem; I wasn't sure if I had the same difficulty. While I understand what you are saying, I find it difficult to see why the metering works well as spot, but not as matrix or centre weighted. Viewing the house today, in A mode, I used spot; focus with the WATE at 16mm and f8 isn't that critical. Worked pretty well, though trying to take pix of the internal cupboards was a bit challenging. (I don't have a flash).

    (And as an example of how not to market an over-priced house...that's another story.)
    (bolded) I hear you, it is puzzling. I conjecture it's a firmware issue rather than a hardware limitation. There are a number of rough edges in the SL's firmware, for sure (most assuredly with the dedicated flash/TTL flash metering system, from what I've been reading elsewhere).

    The SL is still very young in the field. My understanding is that Leica is monitoring all the issues as they come up on various forums and as people send in bug reports and feature enhancement requests. Hopefully, updated firmware will appear reasonably soon.

    G
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    Re: SL and exposure problem with the WATE

    Thanks, Godfrey. I'm relieved that I'm not alone with this strange problem, and that I'm not going gaga. Roll on firmware update!
    Sláinte

    Robert.

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