lightmeter discrepancies Seconic 508 vs Minoltagreenspun.com : LUSENET : Large format photography : One Thread
I rented a Seconic 508 to check against my Minoltal IVF lightmeter this weekend and was surprised by the results. I knew there would be some differences between them but what I found was the that the Seconic reads for less exposure. The oddness is this: the Seconic meter gives about a -2/3f reading in bright sun, compared to the minolta measuring the identical subject but only there is only a -.2f difference when metering in say an interior, much darker area. The meters are different but not in a linear way and I suspect the problem is with my Minolta meter. Anyone know what gives??
-- David Goldes (email@example.com), January 06, 2002
Are you using the 508 on spot? I've heard from several sources now that Sekonic spots are calibrated to a 13% gray instead of 18% (that was it, wasn't it Bill?). Anyway, that might be the reason(?)
-- David Munson (firstname.lastname@example.org), January 06, 2002.
I wouldn't worry too much about the discrepancy. I did exactly the same test when I received my Spotmeter F via eBay. I took it to the camera store (called, strangely enough, The Camera Store), and did a comparison against a Sekonic - it could've even been a 508. The results were rather disquieting - there was a stop difference, but I can't remember which way - doesn't matter, really - the readings were off by a mile.
However, when we compared two Minolta spot meters, the exposure readings were almost identical.
I'd try the comparison again, but do it brand-to-brand. I've heard that Sekonic meters give quite different results. Guess that's the main reason to do basic testing to determine your effective film speed with your lens/film/meter/developer combination.
-- Ken Miller (email@example.com), January 06, 2002.
Curious why the Minolta is automatically suspect? The answer you don't want to hear is it really doesn't matter. After you use the Minolta or the Sekonic for a while you'll start automatically compensating for it's idiosyncracies. (sic?) I love my spotmeter F. I'm guilty after 3 years of using it of knowing how it's thinking and ...tweaking. What really screws you up is when you put new batteries in and have to start the process over again!!
-- Jim Galli (firstname.lastname@example.org), January 06, 2002.
Not to be cynical with this subject but the only non-variable in this equation should be the intensity of the measured light. With a side by side comparison of an incident or a spot meter the readings SHOULD be very close if the meters were properly calibrated. Unfortunately, manufacturing decisions relative to how they decide to present this data leaves much to be desired. Small variances should not be a problem in the film testing as long as the error is linear.
I have seem folks spent thousands of dollars a year on lenses and film and scoff at a simple $40 charge a year to get their meter calibrated. And then they wonder why their results are inconsistent?
Bottom line is - who is to say that any meter (yours or the rented one) are accurate? As a result, I see no reason to spend money on any rented meter when yours could have been sent to any number of quality shops and come back to you dead on. Get to know your meter calibration man or woman on a first name basis. Their importance to your photography is not given the credibility it should IMHO.
-- Michael Kadillak (email@example.com), January 07, 2002.
My guess is that the Minolta is right on and the Sekonic is off (uderexposing). Read this page on my site (Kinesis) for a write-up I did on this topic.
-- Richard Stum/Kinesis (info@KinesisGear.com), January 07, 2002.
Opps, I put the wrong URL on my previous post. I meant to post this page.
-- Richard Stum/Kinesis (info@KinesisGear.com), January 07, 2002.
Meters aren't necessarily calibrated to the same standard and of course might not retain their calibration over a period of use.
I can't think of any good reason to believe that a rental Sekonic is better-calibrated than a Minolta or vice-versa.
I'ts mighty easy to calibrate an incident-light meter (provide you're not in the far north or south); your standard is the sun, and the meter should read 1/EI @f16. Twiddle the adjusting screw until it does so.
Meters will also vary in linearity; that's just the nature of the beasts. With modern meters the error usually isn't huge, while some older meters could be wildly non-linear.
-- John Hicks (firstname.lastname@example.org), January 07, 2002.
Hi Everyone, This is just so funny (strange not Ha Ha), I friend and I working in two different institutions have just been talking about a variation of this same problem. Our Minoltas and Sekonics are exactly the same in Contiuous Mode (thats two Mins & two Seks) but the both Sekonics are one stop under in FLASH MODE. Interesting
Regards Bob Ashford
-- Bob Ashford (email@example.com), January 07, 2002.
Yes, send it to Mr. Milton at Quality Light Metric and I am sure the charge will be a worthwhile expenditure. I have a Minolta Autometer IIIF and Sekonic Studio Deluxe. In incident mode, the two meters do and have always been right on. BTW: the other day was a Sunny 16 minus 1: set the Sekonic to ASA 125, guess what the meter called for at 1/125-Yup-f/11. At sea-level North America, exposures aren't really that difficul
-- David F. Stein (DFStein@aol.com), January 07, 2002.
When my girl friend bought her Sekonic 508 last year I compared it to my tried and trusty Minolta Spotmeter F. I was really surprised to see a one stop difference throughout the scale; her's read one stop under mine. Her 508 seems to be consistent, but it definitely reads under.
-- Ted Kaufman (firstname.lastname@example.org), January 07, 2002.
One thing to bear in mind with this sort of comparison is that the colour sensitivity can vary between different meters.
I use a Sekonic L718 and a Minolta Spotmeter F, and with a grey card the two meters give identical readings at every level of illumination I have tested. However, swap the grey card for a colour chart and there are differences of up to 0.9 stops, depending on the particular colour, with the average difference being around 0.3 stops in magnitude.
I can't really say with any certainty whether it is the Sekonic or the Minolta that is wrong, or whether both are, but I would expect the Minolta to be correct for reflected readings, or it really wouldn't be much use as a spot meter. Certainly I have experienced no obvious exposure problems when using either meter, although in general I use the Sekonic for incident only.
My guess is that David Goldes' discrepancy could (if his meters behave similarly to mine) be accounted for by the difference in colour temperature for the indoor/outdoor comparison.
-- Huw Evans (email@example.com), January 07, 2002.
I used a Sekonic 508 and switched to a Pentax V. The Pentax was 1 1/3 stop different from the Sekonic. My normal EI for the Sekonic 508 was 200 for HP-5+. With the Pentax V, my EI is 520.
-- William Marderness (firstname.lastname@example.org), January 07, 2002.
This is why we calibrate our meters to our lens. Adding to what John stated, also have your lens bench tested and you will find that your lens will vary in exposure... It is useful info when shooting and changing lens. You might be very suprised on how much off your lens will be also. My 408 has a way to adjust the readings (over and under) and I have it matched to my RB system.
-- Scott Walton (email@example.com), January 07, 2002.
it seems to me that if you use the SAME meter all the time and do careful film testing, everything should be fine. if the meter, lens, film and developement are constant with the same meter, it won't really make a difference.
-- howard schwartz (firstname.lastname@example.org), January 07, 2002.
The Sekonic meters are 'jack of all trades..' in as much that they meter all sorts of light from incident to reflected, spot and flash.
Thats why they give you 'Jack of all trade meter readings..'
The Minolta Spot Meter F does one thing only and does it 'spot on..'
I've been using the Minolta Spot Meter F for over twelve years, and if I lost it tommorrow it would be replaced the next day. Its the best spot meter for colour photography available IMHO.
I also have a Gossen Multi-Pro all purpose meter, and the only good thing that it does is getting incident light right.. for everything else you may as well guess.
-- Nigel Turner (email@example.com), January 07, 2002.
All this talk about meters is really cracking me up. Zillions of posts about lenses, coverage, etc., and everybody is out there just fling blind. Just got my two, Spectra Combi-500's back from Burbank where they were calibrated. In a test with both Spectra's, a Pextax 1/21, and Three Canon EOSv-1's on a grey card, the error range was less than 1/10th of an F stop...between all meters. It's amazing the amount of blind faith, shooters will place in a light meter's accuracy, right off the dealers shelf,.. and yet ramble on about lenses. Now, with a shutter tester telling me that some of my newly serviced LF shutters are running 30% slow at the higher speeds, at least I can know what my true light is, and how my shutter is reacting. Somehow, somewhere, somebody got the idea that this zone system stuff was a science...when it is actually an art, and a variable one at that. It will become more of a technical arena when shooters pay more attention to that little light meter in their hand, and less to the super whatchamacallit lens, mounted on the front of their super-turbo large format camera. If that little light meter is not accurate, and you don't know your real LF shutter speed is, you're screwed from the beginning...and everything you do will have an automatic error factor built in,....from moment one. Good luck.
-- Richard Boulware (firstname.lastname@example.org), January 07, 2002.
hi david... i have 3 pentaxV meters and they are all a .3 stop off from each other! i have tried to get them to read the same but without success. good luck. remember to bracket on the over side and cut back on the development as usual. call ok
-- rich silha (email@example.com), January 07, 2002.
As you will recall from early science classes: reliability is often more important than accuracy-of course, both would be nice. Two manufactures may have different opinions on what is important criteria to base exposure calculations- a lot of in camera meter makers think their customers shoot alot of faces on slide film. Sekonic makes a variety of pro meters for television and movies. That's why books and information talk about adjusting film ASA and developement to your own equipment and shooting style. As long as your meter is reliable-that it gives you the same measurement each time in a somewhat linear fashion is actually the big concern. The minoltas are greaat meters unless something has happened to make it malfunction-use it with confidence and proceed accordingly! Balancing a meter is an art-Quality light metric in Hollywood can do it but you better hurry as I think he may be retiring soon.
-- Jack Nadelle (firstname.lastname@example.org), January 08, 2002.
All these posts make me glad that I have a Zone VI modified meter.Pat
-- pat krentz (email@example.com), January 08, 2002.
Wow--asking a group of LF photgraphers about light meters certainly gets a response. The consistent response about Seconic meters underexposing though is helpful. Thanks to all--
-- David Goldes (firstname.lastname@example.org), January 10, 2002.
I don't know what all the fuss is about in regards to the Sekonics...we've used 2 L-328s for more than 10 yrs. and they've been real workhorse meters in the studio and on location....I liked them so much I bought one for myself a few years ago. They may vary a slight .2 of a stop at times, but who cares? You're gonna quibble about that? It all has to do with how you use the meter, we use them with the flat diffusers, and you have to know where & how to place the sensor...BUT in the end with LF, what matters most is like someone else has said...what your lens & shutter is really doing...and what your bellows factor is, and how your process is running....if you get everything tuned to your shooting style, and are consistent what does it matter? In the end, that's what polaroid is for....
-- DK Thompson (email@example.com), January 10, 2002.
I've just tested my Sekonic 508 versus Minolta flashmeterV (incident mode wich I use 90% of the time) difference is 0.1 F stop!
-- Jean-Marie Solichon (firstname.lastname@example.org), January 11, 2002.
How did you guy´s do the testing? I have 3 meters a minolta F spot, a Mastersix Gossen and a Bron meter and if I do the test very exactly dey are only in differences like 1/10-2/10m f stops. Only the mastersix has in very bright sunlight or flashlight the thendency to underexpose 1/2 f stop. But I know it and I compensate it. You should know your equipment! Good light, to all!
-- Armin Seeholzer (email@example.com), January 11, 2002.
I dont see the problem with mine, I have a 508 and I love it! To test it I took an incident reading on a sunny day and it was dead on with the sunny 16 rule, I then took a spot reading of a gray card and same thing, it was dead on! You can compare all the meters you want but the real test is how they preform in the situations you use it most and how you can compensate their "inaccuracies" by testing.
-- Jorge Gasteazoro (firstname.lastname@example.org), January 11, 2002.
Hi David- Strange to see you lurking aming the LF photo nerds (wait a minute, I'm here too?!) I think you're lucky to have a maximum 2/3 stop dif between meters. The Sekonic 506/608 looks very nice. I've been happy with my 408, although I've had to do several home repairs on the flash sync socket. I second the previous thought about the non-linear response being due to spectral sensitivity differences between meter cells. If you tested outdoors in daylight and indoors in tungsten, that would do it. Give me a call, we've got more important things to talk about. -Paul
-- Paul Shambroom (email@example.com), January 11, 2002.
I have brought a Sekonic L508 recently. I have made a comparison between my new L508 and my old Minolta IVF (with a 5 degree viewfinder). I find the measuring difference on both incident light readings(in day light situation), non-cord flash mode, and spot readings ( I use 4 degree for L508 and 5 degree for IVF) are less than 0.1 stop difference. However, I am surprised by the result of incident reading under Tungsten light situation. The L508 reading has 0.4-0.5 stop than my old Minolta IVF.
-- Teddy Wu (firstname.lastname@example.org), February 08, 2002.