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09-05-2011, 07:48 AM   #1
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Stupid LX meter question

It will meter through a 9-10 stop ND filter won't it?

Obviously with compensation for Reciprocity failure taken into account of course.

09-05-2011, 08:02 AM   #2
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Of course In manual mode as long as there is enough light.In aperture priority auto expose, it will stay open until it has accumulated enough. For instance I have successfully exposed frames over 1.5 hour long.
09-05-2011, 08:26 AM   #3
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One thing for sure, you're going to be hard pressed to compose and focus with a ND that dense attached in all but bright conditions. You can always get your meter reading when you have it off to compose and apply the 9 or 10 stops to your indicated time.

I believe the stepless automatic exposure range for the LX extends down to EV -6.5 for ISO 100. So that means you won't be able to meter through the ND filter for low light scenes in the EV3 or EV4 range as middle gray. And I don't know how the meter is going to react when it can't "see" the lower values in the scene if EV3/EV4 is the middle. I guess you'd get a middle gray bumped up a few stops. So to play it safe, I'd consider EV6 or so the lowest light level to meter through that dense of a ND filter.

And in manual mode, I believe the meter is EV1 as the lowest. So that means even higher light levels to meter through those ND filters.

Last edited by tuco; 09-05-2011 at 09:26 AM.
09-05-2011, 10:38 AM   #4
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QuoteOriginally posted by tuco Quote
I believe the stepless automatic exposure range for the LX extends down to EV -6.5 for ISO 100. So that means you won't be able to meter through the ND filter for low light scenes in the EV3 or EV4 range as middle gray. And I don't know how the meter is going to react when it can't "see" the lower values in the scene if EV3/EV4 is the middle. I guess you'd get a middle gray bumped up a few stops. So to play it safe, I'd consider EV6 or so the lowest light level to meter through that dense of a ND filter.
For sure this is the technical specifications of the light meter. In actual application I have tested the LX to successfully meter over 2 hours and longer as it will continually meter the scene until it has received enough light. Keep in mind that when you do test this, the IDM reads off the film and the pressure plate is not exactly the same reflectivity of film. Of course since this is beyond technical specifications YMMV. However, the results have been consistent in the numerous tests I have conducted but I am not sure if this is consistent across all LX's.

BTW, OM4 will continuously meter OTF but cutoff at 2minutes, Nikons will meter the scene at the time of shutter activation with no cutoff time and will not deviate, Canons - and others, act like Nikons but will cutoff at 30 seconds or less.

09-05-2011, 11:46 AM   #5
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QuoteOriginally posted by LesDMess Quote
For sure this is the technical specifications of the light meter. In actual application I have tested the LX to successfully meter over 2 hours and longer as it will continually meter the scene until it has received enough light.
What about the film's reciprocity? A metered 6 min exposure can need as much as 1 hour for a corrected exposure for some BW films.
09-05-2011, 11:56 AM   #6
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No doubt each film's reciprocity has to be accounted for but I would personally have to test it to be aware of what it will really look like at the end of my workflow - given the scenes lighting and all. Here is a result of about a >10 minute exposure as metered by my LX using Fuji 100. As you can see lights on the pier were on as this was in the twilight hours. I wasn't sure what I needed to smooth out the Atlantic Ocean but now I know the difference between a 30 second and >10 minute exposure. These are straight up scans from the Coolscan 9000 with no pre or post color correction.



Link to larger image -> http://www.fototime.com/773634514E5AF6D/orig.jpg
09-05-2011, 12:43 PM   #7
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I've also conducted some controlled long exposure testing with other films like this one of Kodak Gold 100.



Ling to bigger version -> http://www.fototime.com/23DFB85821254E5/orig.jpg
09-05-2011, 05:49 PM   #8
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To blur the ocean is a function of how active it is. This is only 4 minutes and I didn't have to worry about reciprocity at all because I used 100 Acros which has a simple rule: apply 1/2 stop of additional exposure after 120 seconds.






And no doubt this would have looked pretty much the same at 30 seconds as the 60 second exposure it was taken at (100 Acros).







Last edited by tuco; 09-05-2011 at 05:58 PM.
09-05-2011, 06:03 PM   #9
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QuoteOriginally posted by tuco Quote
To blur the ocean is a function of how active it is.
There are indeed quite a few variables that we won't realize until we try it. Beautiful images you have there!

As you can see from my own workflow's results, I have yet to worry about it. To be sure, I actually call it reciprocity characteristics rather then failure
09-05-2011, 06:22 PM   #10
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Les, your crayon box sets illustrate the remarkable capabilities of modern films.
How much digital post-processing do you perform on these images?

Chris
09-05-2011, 07:13 PM   #11
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Chris, On both of these my typical workflow using Coolscan 9000+Nikonscan+auto focus/expose and ICE with all other controls off or neutral and no pre or post adjustment of any kind except for crop, orientation and copyright and text.

I agree that modern films are really remarkable!
09-06-2011, 08:09 AM   #12
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QuoteOriginally posted by LesDMess Quote
Chris, On both of these my typical workflow using Coolscan 9000+Nikonscan+auto focus/expose and ICE with all other controls off or neutral and no pre or post adjustment of any kind except for crop, orientation and copyright and text.

I agree that modern films are really remarkable!
I don't mean to be picky Les, but in the crayon test it's possible that the scanner did a large amount of exposure and colour adjustments prior to presenting you with the image.
I know the autoexposure feature on my Epson V700 will automatically compensate for quite a large amount of under or over exposure, etc.

This is a rather interesting thread - and the above is about all I can add to it!
09-06-2011, 08:36 AM   #13
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goddo, I don't consider it being picky as I agree that the Nikonscan+Coolscan 9000 autoexposure does some adjustments which is not obvious since this is a color negative. I can only find the spec sheet for the Superia 200 and it states to add +1 stop exposure for duration up to 64 seconds. If that is similar for Fuji 100 then I can guarantee you that autoexposure will level it undetectable. In fact, I have overexposed negatives by +5 (or much more) and it is still very usable with the most basic of post processing.
09-06-2011, 11:07 AM   #14
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FWIW traditional wet darkroom and even minilab printers often apply a similar degree of exposure adjustment.

In the old days a photo magazine film test usually included a complete lab analysis, including
sensitometer and densitometer measurements, etc. One can't expect the same from a hobbyist.
If the negatives are of comparable density, adequate for normal printing/scanning that's good enough for me.

Les, is there a home page with links to all your film tests, and describing the procedure?

Chris
09-06-2011, 08:06 PM   #15
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Chris, Unfortunately, I have not setup a website/blog or whatever to hold the the film testing that I have conducted.
Below is an example of the exposure range testing that I have conducted for Fuji 100 using my LX. I metered the gray card behind the box and it indicated optimum at 1/60 so I held the aperture constant and started at the top of the LX speed range at 1/2000 (-5 stops) all the way to 8sec (+8). You'll notice that the Nikonscan+Coolscan "autoexposure" makes -3 to +2 practically the same. With a little post processing and possibly exposure variation in Nikonscan, I can easily recover -4 and +6.


Larger vesion pic link -> http://www.fototime.com/5662A1CA253B2E0/orig.jpg
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