Improvising a Spot Meter using a DSLR?

[Omega]

Well im in a bot of an annoying situation at the moment, i will be going to the German Alps next week, and well... The Sekonic L558 Spot meter i was going / by the time you guys read this post, have ordered. Is due to arive 3 days into the trip. Thus i wont have a proper Spot meter with me. So i was wondering, could i use my Sony A350 DSLR with a 300mm Lens as a sort of improvised spot meter, for large format.

I have tryed it using MF, with some pretty good results. However, i do not have the time to test it with LF before the trip, as developing the film would take too long, and would meen i would be one film holder short.

Thus i was wondering could it work? By the way, i shoot primarily landscape and macro Photography, the latter only in digital, as my MF camera cant focus close enough. And some long duration exposures, also using the DSLR, and i have tried it with some B&W film in my MF camera, but i haven't seen the results yet.

The camera i will be taking with me is a Super Speed Graphic, with a Rodenstock Optar 135mm F4.5 Lens.

The films i intend to use are Kodak Ektar 100, Foma Fomapan 100 (with hoya Orange filter) and Rolli IR 400 with a hoya R72 filter.

[Bill_1856]

Omega,
Your problem sounds very similar to what I will be facing in two weeks at a workshop.
My original intent was to take a 4x5 Crown Graphic and a light meter, with pocket digital camera for "backup. Since I do very little film photography these days,I haven't checked out the meters recently. My preference is a Weston EuroMaster, last calibrted by Quality in 2001. I also have Metrostar, Leica MR, Pentax digital spotmeter, and several built into cameras, as well as Sony RX10 and RX100 digital cameras (those two agreed exactly).
I was appalled at the variation between the different meters. most differed by one stop, but a couple (including the Weston) were two stops or more different.
In short, finally decided to use the RX100, which has a spot function, as well as centrally weighted.
Good luck!

[Michael E]

In general, there is nothing wrong with using a DSLR as a spot meter. The zone system works just the same. But you should definitely run a test before you go on your trip.

I once dropped my spot meter in Yosemite NP on the second day of a four week US trip. I had to guess the exposure for the rest of the trip. The f16 rule works surprisingly well in the american south west. Don't know about the Alps.

Michael

[Greg Miller]

There's at least one existing thread on this site about using a DSLR as a meter. Do a quick search and you should find a lot of existing information,

[Greg Miller]

http://www.largeformatphotography.info/forum/showthread.php?108235-exposure-issues-using-a-DSLR-as-a-lightmeter&highlight=meter+dslr

[Omega]

I did test the DSLR as a spot meter before, using Ektar 100, in most shots the images were about 1 stop under exposed. Funny enough the shot i thought i fried by over exposing it turned out fine. I guess i will need to compensate for this then. I have also developed a new technique with my DSLR, but i haven't gotten the results back yet. Also thank you for the other thread! I don't think i will be taking the Rolli IR film with me then, since i cant trust the exposure reading on my digital cameras (Sony's and a Nikon) the spot meters on them vary by about 1 stop.

[Omega]

Well here is an update, i decided to go with the Sekonic l758, as it only cost 40 bucks more then a used 558 (with pocket wizard transmitter), since i do not need that i went with the 758, and it should arrive in time. Well lets hope it dose in deed.

[hoffner]

I have tryed it using MF, with some pretty good results.

Thus i was wondering could it work?
The camera i will be taking with me is a Super Speed Graphic, with a Rodenstock Optar 135mm F4.5 Lens.



Well here is an update, i decided to go with the Sekonic l758, as it only cost 40 bucks more then a used 558 (with pocket wizard transmitter), since i do not need that i went with the 758, and it should arrive in time. Well lets hope it dose in deed.

Will be holding my breath up to next announcement. Meanwhile, could you explain - when your digital camera meter worked well for your MF pics, why wouldn't it work for LF too? What's your personal exposure factor for bigger film format when you measure the exposure? Just curious.

[Stoogley]

What have you been using to measure exposure for your LF work?
Go measure some scenes with that and your DSLR and compare.

Then you'll have a baseline for the DSLR that should be pretty close if not right on.

[VictoriaPerelet]

F/16 1/100sec at iso 100 is same for point and shot, MFDB, 120mm film camera or 8x10. Light meter is single pixel camera after all.

That is one basic fact of photography. They used to have photography classes in high schools not so long time ago.

But then 1kg of iron does feel much heavier than 1kg of air. And you need to calibrate your scales. Some topics can be debated for ever:)

[hoffner]

F/16 1/100sec at iso 100 is same for point and shot, MFDB, 120mm film camera or 8x10. Light meter is single pixel camera after all.

That is one basic fact of photography. They used to have photography classes in high schools not so long time ago.

But then 1kg of iron does feel much heavier than 1kg of air. And you need to calibrate your scales. Some topics can be debated for ever:)

Sounds incredible! Don't know about you, but personally I use PEF (Personal Exposure Factor) for each film format. So for 120 it is the exposure meter value, for MF my PEF is 1x for LF it is between 1.0 x to 1.00 x, depending on the precise film format. Works a whole heck, never missed an exposure because of a wrong PEF.