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09-12-2010, 01:19 AM   #1
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f/stop in Raw or EXIF (using MF lenses)

Is there a way to record f/stop information when shooting with manual lenses without using external software.

I know it's possible using software but here I am looking for a way to do it in camera. Sometime after shooting so many picture, it's simply not possible to remember which picture was taken at which f/stop.

09-12-2010, 07:23 AM   #2
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Unfortunately, I don't think there's a way. Guess you'll have to resort to pencil and paper, like in the old days!

Adam
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09-12-2010, 07:33 AM   #3
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I guess it would be nice feature if you could manually tell the body what aperture you are using (similar to the way you enter the focal length for the SR system) such that it could then be recorded to the EXIF data. Obviously you would then have to change the setting every time you adjusted the aperture, but I suppose that would be no more time consuming or difficult than writing the information down separately.

Would probably be a pretty easy addition (in terms of programming), but I wouldn't hold my breath on a feature like that being implemented in the future

As an added bonus, if the camera had that information (and the max aperture of the lens), perhaps it could then meter in "Av mode" without having to use stop-down metering... just a though.
09-12-2010, 08:47 AM   #4
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QuoteOriginally posted by Adam Quote
Unfortunately, I don't think there's a way. Guess you'll have to resort to pencil and paper, like in the old days!
Adam, you have touched on my most wished for feature, the ability to add voice annotations to my photos. After all the K7 already has a microphone. I would love to be able to add a short voice message to my photos. There are many times I would like to add a note to my photos and to pull out pen and paper is a lot of extra hassle.

I think quite a good compromise would be to use the Livescribe SmartPen
Review: Livescribe Pulse Digital Pen/Recorder (Verdict: It's Good for Notetakers)

Peter

09-12-2010, 09:56 AM   #5
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The most common EXIF editing features don't even let you go back and add this information later.
09-12-2010, 01:22 PM - 1 Like   #6
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Old tricking trick

Well there is still the way like I use my fully manual lenses - by tricking the camera into thinking there was a non-manual f/1.2 lens attached. Lets you use all camera modes (Green, P, Sv, Tv, Av, TAv, M, B, X and User) and therefore eliminates the need to use stop-down metering and gives you matrix metering.

Good thing: it's very easy to do. Just put something conductive on the recessed A-pin - so that lens mount and camera bayonet/mount are connected.
I'm using aluminium-tape. Doesn't last forever but is doing a great job for like half a year now.

Bad thing: you have to adjust aperture setting on both the camera and the lens. The camera thinks it could control the aperture and infact it does but because of different aperture machanisms in pre-A lenses it isn't doing it right.

Bigger annoyance: every lens will be seen as having a max. aperture of f/1.2 (and it needs to be that way otherwise stopping down won't work right on these lenses) - so to get the exposure right you have to use exposure compensation.
For a lens with a maximum aperture of f/2.8 this means EV compensation needs to be set to -2.5 (f/1.2--->f/1.7 = 1 stop, f/1.2--->f/2.4 = 2 stops, f/1.2--->f/2.8 = 2.5 stops).
This however means using slower lenses than f/3.5 will most likely result in chronic overexposure if you're using a camera only allowing for +/- 3EV compensation. K-x, K-7 and soon K-5 owners don't have to care with their luxurious +/- 5 EV...

And there's another limitation to respect: Unfortunately the whole thing only works perfectly with lenses slower than f/1.2 and faster than f/3.5. Because of that said change in aperture machanism there won't be enough actuation on a very fast lens to stop the aperture down to your setting. Slower lenses won't have that problem (but see above - overexposure).
The fix I used for my f/1.4 lens was to unmount it slightly so it just works as any M42 lens (without an A/M switch). Set aperture on camera and lens and either lock exposure before you stop down or use EV compensation accordingly (stopping down will result in actual darkening so if not prevented metering will mess up). Yes I know this is way more complicated than using it in stop-down mode. But having program modes and matrix metering together with full EXIFs means more to me.

About modes: yes, you could use every mode you can use with an A-lens but I recommend sticking with Av, TAv, X, B and M - other modes may pick an aperture value not actually available on your lens.

But that's about it. For me it is absolutely woth the "trouble" as you get almost all benefits of an A-lens without having one. And if you don't mess up you get correct EXIF-data, too.
09-12-2010, 02:19 PM   #7
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Egg salad, you can always mask some contacts (by adding insulating tape to your lens) in order to have an accurate max aperture (see Bojidar's site).
09-12-2010, 02:49 PM   #8
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Yes, I am totally aware of this. And initially I tried to code every lens to its real aperture. But as I said before because of different conversions (linear vs. logarithmic if I'm right) aperture movement varies between pre-A and A lenses.
So while you will have totally matching aperture selectable on camera giving you perfect exposure in theory you won't get anything working right since the aperture won't be stopped down enough. To use the whole trick there must be some "tension" on the aperture lever. This is why it only works with lenses slower than f/1.2. And this is also why ~f/2.8 will work best. There is a difference of 2.5 stops which in turn means the camera would want to move the aperure lever roughly this much more than you let it by setting the aperture on the lens itself and thus preventing it from stopping down further.

At first I was slightly concerned to damage the whole mechanism in-camera.
But by examinig the mechanism I found it is spring loaded. So the needed tension is created by a simple coil spring. And while I'm no expert I don't think that would likely endanger the stop-down mechanism.


What I totally forgot to add: You also get working P-TTL with all lenses this way.


09-12-2010, 03:43 PM   #9
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Actually, there is, In theory (of mine) a way it could be done. Exposure Value (EV) is a calculated number based on shutter speed and aperture (and ISO). Knowing what the EV is from the meter readings (which is recorded in EXIF) it is possible to extrapolate the aperture, or at least get close enough to it.

Exposure value - Wikipedia, the free encyclopedia

From what I can tell, all segments on the meter are active and recorded. Only the selected metering type is used for exposure however. That is if you (like I) use only spot metering, then only the center value of the meter matrix is used for exposure, making it pretty simple to get a relatively accurate EV for the calculation. It may become a little more difficult for CW and Matrix but the center point would still give a reasonable best guess at the Aperture used at exposure time.

09-12-2010, 04:23 PM   #10
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QuoteOriginally posted by GeneV Quote
The most common EXIF editing features don't even let you go back and add this information later.

Exiftools, which is a free download, allows you to modify any existing EXIF value or add your own. So, it is easy to add aperture setting to a file, if you know what aperture it was shot at.

Paul
09-13-2010, 01:25 AM   #11
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The only way to do this would be by wiring the lens mount and manually insulate/short these wires to match the actual aperture used...
Problem is that you'd be limited to f/8...
09-13-2010, 04:26 AM   #12
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Sorry but I don't know what you are trying to say. Why should I be limited to f/8? Are you talking about the semi-A "mode" or the use of any manual lens as M42 lens?
09-13-2010, 08:31 AM   #13
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I agree with Adam. The only tried and true way to overcome the crippled mount limitation is to note your working aperture in a photographer's logbook and then add the f-stop in post. Either exiftool, or for linux users the faster exiv2, can do that easily. This requires a degree of rigor not particularly well-suited to the faster-paced world of digital photography.

Jack
09-13-2010, 11:18 AM   #14
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QuoteOriginally posted by jbinpg Quote
I agree with Adam. The only tried and true way to overcome the crippled mount limitation is to note your working aperture in a photographer's logbook and then add the f-stop in post. Either exiftool, or for linux users the faster exiv2, can do that easily. This requires a degree of rigor not particularly well-suited to the faster-paced world of digital photography.

Jack
Another good tool is jhead
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