New Light Meter readings to Old Lens Converter : LUSENET : Large format photography : One Thread

Hi all:

I have recently gotten into 4x5 and use a Nagaoka. It came with a nice Graphex 203mm and I recently picked up a 90mm. They shoot pretty well (to my untrained eye) and are super small, making it possible for me to take the 4x5 on an upcoming motorcycle trip through Europe. However, I have one difficulty.

My Sekonic meter reads standard 1s, 1/2s, 1/4s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s etc. but these lenses are set for 1s, 1/2s, 1/5s, 1/10s, 1/25s, 1/50s, 1/100s, 1/200s, 1/400s. Is there a converter for the f stop that my meter indicates to give me the proper exposure time given my older lenses? Thanks!

-- Joe Nagy (, May 14, 2002


Hi Joe, I wouldn't worry... The speeds indicated in the shutters seldom corresponds to reality . P_lus the difference between 1/400 and 1/500 is not going to affect your exposure.

If it means a lot to you , you can work on the f/stops and we are talking about 1/5 of a stop.difference, if the shutters speeds are exactly the ones claimed to be, .....and i doubt it.

-- domenico (, May 14, 2002.


I, too, have a Sekonic meter. I haven't had to use the 1/100, 1/200, etc. shutter speeds yet, but I believe that my meter (an L-508) does have them, so your's may, too. I think that you get to them (on the L-508, anyway) by turning the dial past 1/8000.

As Domenico said, the actual speeds could be very different from the marked ones. I read once that you can take a 35mm camera to a shop and get a graph of the actual shutter speeds. You may be able to do this with LF gear, and if the speeds are blindingly inaccurate have the shop recalibrate the shutter.

-- Matthew Runde (, May 14, 2002.


Pretty much all modern meters will have the same 'problem' as your Sekonic. I use a variety of modern and older shutters, and pretty much guess-timate the placement of say, 1/5 between 1/4 and 1/8, et cetera. Actually, I so rarely use speeds faster than 1/2 a second, I rarely have to think about it.

-- jason (, May 14, 2002.


Not only that, but how do you know that your 1/5 is really 1/5 and your 1/50 is really 1/50. What you really need to do is calibrate your meter to your shutter for the film and processing you are going to use before you go on that trip.


-- Kevin Kolosky (, May 14, 2002.

Joe, I just had my Ektar 203 cleaned and adjusted, and it's surprising how accurate the old Supermatic shutter is with the exception of the highest speeds. I try to expose to the nearest 1/3 stop when possible and have taped a small label on my lens board with approximations of the shutter speeds to the nearest 1/3. I indicate them with plus and minus signs relating to the standard shutter speeds. For example 1/60+ would be 1/3-stop faster than 1/60; 1/30- would be 1/3-stop slower. I make the fine adjustments with the aperture setting. Therefore, for what it's worth, here are the conversions for you in milliseconds (thousands of a second) and in my system as well. Remember, in this scheme, plus means faster, i.e. less exposure and minus means slower or more exposure.

1/5 sec = 200 milliseconds or 1/4+

1/10 sec = 100 milliseconds or 1/8+

1/25 sec = 40 milliseconds or 1/30-

1/50 sec = 20 milliseconds or 1/60-

1/100 sec = 10 milliseconds or 1/60+

1/200 sec = 5 milliseconds or 1/250-

1/400 sec = 2.5 milliseconds or 1/500-

Also keep in mind that, unless you have had your shutter calibrated, you don't know the actual performance. I have mine tested regularly and take the average millisecond value of three or four firings at one speed as a basis for figuring the speed to use to the nearest 1/3 -stop (i.e. 1/15+). Most shutters are fairly consistent, just not necessarily in agreement with the marked speeds. You might want to have yours tested if accuracy is important in your work. If you already have a generous "fudge factor", you could just use the nearest standard stop. Hope this helps, ;^D)

-- Doremus Scudder (, May 15, 2002.

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