Sekonic Light Meter - error? Calibration?
Alan Browne
I saved a bundle as the previous owner never had it out of the box and
returned it to the store after 2 weeks just as I was picking up/dropping
off film for developing. The owner of the store knew that I was looking
into meters (specifically the Minolta Flash Meter V) and she opened the
door. I saved over $400 (CDN) v. the Henry's list price. (The store
had sold the unit under a Sekonic school promotion, so the saving over
that price was a bit over $100 CDN).
So, I bring the meter home and set up a test.
The ambient test went like this.
1) Light up a subject with a 500W photo bulb. The subject is a
bookshelf of National Geographic magazines. The light is normal in the
horizontal to the subject and about 15 degrees above (eg: shining down
to the subject).
2) The camera is about 10 feet away, set to ISO 1600 with a 28-70 f/2.8
lens. It is level with the bookshelf and about 30 degrees off
horizontally. (Minolta Maxxum 9 and Minolta lens). It is set to spot
meter. Exp. comp is zero. And metering is in 1/2 stops. I set the
speed to 1/250.
3) I meter with the camera. The area under the center exp spot of the
camera is about the same as that of the spot meter on the Sekonic
meter. The reading with the camera is 250 f/5.6 The reading with the
meter is 250 f/8.0 (+0.1 stop).
4) So, I put up an 18% grey card. The reading with the camera is 250
f/4.5 The reading with the meter changes to 250 f/5.6 (+0.1 stop)
5) The incident light reading for 250 comes to 4.0 (+0.5 stop); eg:
f/4.5. I would have expected this to be identical to the grey card
reading.
So, I am perturbed about the Sekonic L-508. I know that my Maxxum 9 is
very reliable for reflected and flash exposure. So it would seem that
the light sensor in the L-508 is biased.
Comments anyone?
Alan
--
Lert's live longer.
Be A Lert.
Dilbertdroid2
very reliable for reflected and flash exposure. So it would seem that
the light sensor in the L-508 is biased.>>
Why get perturbed about the meter? You haven't done anything to quantify it's
alleged inaccuracy, so at this point you are just guessing. How does the film
look? Shoot some pictures of a Macbeth color checker on slide film and see
how it looks.
And if your Maxxum 9 is very reliable as you say, why waste money on a
hand-held meter? Doesn't make much sense.
ClaudeDB
Alan,
Welcome to Sekonic's independent world of exposure. I had an L-508 and observed
the exact same 1/2 stop underexposure. I verified this with an exposure series
of Kodak targets, and also by comparing to Minolta and Pentax light meters. If
you go to Sekonic's website, they have a bulletin board where several L-508
owners have experienced the same problem. I've talked to a Mamiya rep
(Sekonic's importer) who verified that the meters are calibrated to a 22%
reflectance, not 18%. I have heard from other sources that Sekonic uses a new
ANSI standard for light calibration. That's fine, expect you'll end up with 1/2
stop underexposures regardless. The solution is to simply use the manual
compensation mode that allows you to dial in any permanent exposure bias (see
your manual). But make sure you still get consistent readings (compared to your
camera's meter) over a wide range of lighting and not just one light setting.
Otherwise, it's a very nice meter.
Claude
Alan Browne
techniques.
Alan Browne
Thanks for your comments. Although I read the pertinent parts of the manual for
incident, reflective and flash metering, I didn't see anything about bias... but at
your suggestion, I'll try it (There it is on P. 24 of the manual ... hadn't gotten
that far).
My key concern here will be to make sure that the bias offset is constant from
f/1.4 through f/32 at various speeds (pretty slow to 2000 or so). I'll do these
tests tomorrow in low light, 500W, 1000W, and with a variety of flashes. I figure
about 18 test points (36 measurements) should cover it. I'll post the results (if
they make any sense.) I mention this because it is highly dependent on the way
Sekonic convert the physical measurment of light into f/stop-speed settings. If EV
(or similar) is the pivot, there should be no problem.
For flash testing in M mode, I'll do a few color tests with some contrasting colors
& shadows. (at 0 comp and at whatever bias I determine) on Echrome 100. If I ever
figure it out, I'll post the results.
Thanks for your help.
Cheers,
Alan
ClaudeDB wrote:
>
> Alan,
>
> Welcome to Sekonic's independent world of exposure. I had an L-508 and observed
> the exact same 1/2 stop underexposure. I verified this with an exposure series
> of Kodak targets, and also by comparing to Minolta and Pentax light meters. If
> you go to Sekonic's website, they have a bulletin board where several L-508
> owners have experienced the same problem. I've talked to a Mamiya rep
> (Sekonic's importer) who verified that the meters are calibrated to a 22%
> reflectance, not 18%. I have heard from other sources that Sekonic uses a new
> ANSI standard for light calibration. That's fine, expect you'll end up with 1/2
> stop underexposures regardless. The solution is to simply use the manual
> compensation mode that allows you to dial in any permanent exposure bias (see
> your manual). But make sure you still get consistent readings (compared to your
> camera's meter) over a wide range of lighting and not just one light setting.
> Otherwise, it's a very nice meter.
>
> Claude
--
Anders Svensson
> So, I am perturbed about the Sekonic L-508. I know that my Maxxum 9 is
> very reliable for reflected and flash exposure. So it would seem that
> the light sensor in the L-508 is biased.
>
> Comments anyone?
>
> Alan
When you are using your camera, you add errors from the lens
aperture coupling and add a lens transmissivity factor. The
f/ stops on the lens are usually numeric (nominal). (T/
stops are corrected for lens light loss).
Then, you have the added error of the camera showing half
stops - the rounding error has to be considered as well. In
other words, 250/f8 and 250/f5.6 *could* show just a half f/
stop difference.
Thirdly, different metering cells may have a slightly
different response to differently colored light (wavelength
response).
I would not think that it necessarily constitutes a problem
with either meter. If the Seconic is consistently off by
half a stop (as suggested by another poster - and it might
well be), a slight adjustment to your preferences is simple
- by mental or physical adjustment :-)
--
*************************
Anders Svensson
mail: anders.-.ei...@swipnet.se
*************************
Bob Hickey
you'll find out more about the film you're using. Films are rated by
standards, not by how the pictures look. If your 400 film comes out the
way you want it rated at 217 7/8, then that's what it is; what happens
in between, who cares. I have all kinds of cameras floating around, but
I always use the same meter.
Bob Hickey
Alan Browne
The error, as I measure it at 12 points is +0.8 stops (actually 0.75, so rounded is
.8).
Dial in -0.8 on the L-508 and the camera and meter agree througout the range of
f/stops on the lens.
Then prompted by the message from Anders Svensson... change lenses. Since I was
using high end glass for the test, I switched to a consumer grade bit of caca
(Minolta 28-80xi), possibly the worst AF lens in history (although I have taken
some wicked good shots with it in the past, it has had its focus behaviour problems
at the worst possible times...)
Now the discrepency between the camera and the (bias corrected) meter is about +1
stop. So, if I rely on the meter ... I will get a 1 stop underexp with the 28-80xi
lens. Sigh. For a "snap" who cares, let the camera meter figure it out. But for
a portrait or landscape... sigh. (not that I'd use that lens, but as I switch
lenses who the heck know what I'll get in the end with a bias of any kind
programmed.)
After rational thought, Anders is right ... the transmissiveness of the glass is
different (even if I remove the filters (eg: UV 0)). The point was driven home
when I realized that upcoming B&W photography would be done with a deep red filter
(-2.5 stops). The camera meter of course will just see less light. The handheld
meter will see it like it is...
The only rational comparison I can make is with another meter. Not against a
variety of lenses and a camera. And then the question is .... which reference is
correct?
So ... what next. Does it matter? Since my intention of using the meter is to
compare different areas of the scene, or measure different light sources it doesn't
matter. I merely need to know how many stops down (or up) a shaddow (or highlight)
is to (attempt to) control it in the exposure I'm making. Or the ratio of various
light sources, or the flash intensity from multiple sources (or reflectors).
In the end: Dial in -0.5 stop for the alleged difference. And get on with life.
The real test will be when I try to control areas in a scene and if those areas are
rendered the way I (attempt to) control them.
Coincidently with the purchase of the meter I bought a couple rolls of T-max 100
and 400. So some sky-heavy, red filtered wide angle landscapes are coming up.
Thanks,
Alan.
ClaudeDB wrote:
--
Paul Mozell
stack of sheet film, finding everying 1/2 to 2/3 stops underexposed. I
was using either a Gossen Digital F or Gossen Luna Pro F with the
spotmeter attachment. This is driving me nuts. Clearly, Gossen's
definition of 18% grey has no relation to Nikon or Canon - where my
35mm outdoor exposures are generally right on.
Alan Browne <alan....@videotron.ca> wrote in message news:<3BCCFA5A...@videotron.ca>...
Pat Chaney
> And if your Maxxum 9 is very reliable as you say, why waste money on a
>hand-held meter? Doesn't make much sense.
Ever tried incident light metering on a Maxxum 9?
Pat
--
Photos at:
http://www.shuttercity.com/ShowGallery.cfm?Format=Cell&AcctID=1251
Richard Stum / Kinesis
Seondly, my L508 (and other Sekonics always underexpose 2/3s a stop).
To adjust this problem visit my site
http://www.kinesisgear.com/opinion.html where I have posted my
complaint on this matter.
Richard Stum
> > > >3) I meter with the camera. The area under the center exp spot of theI
Alan Browne
want to know how useful it is in that mode. It appears great for incident mode (with 0.5
to 2/3 stop compensation).
Although I'm beginning to wonder why I didn't save more pennies for the Minolta 5 (it
does not have reflected mode w/o an attachment is one reason).
I read your link below. Thanks.
Alan
--
Glenn de Souza
with a few minor differences. I tested using E-6 slide film using a subject
holding a grey card in both open shade and direct sunlight. My three films
were E100S, Fuji Astia and E100VS. With all three films I found ambient
metering underexposed 2/3 stop in incident mode and 1/2 stop under in
reflected spot mode. My Leica in camera meter was dead on.
For some reason, I have found flash metering to be dead on accurate. So this
means I do the exposure compensation of +.5 in ambient reflected mode, +.8
in incident, and I leave flash alone.
As a personal choice, rather than fool with the EV setting which disappears
unless you call it up, I reset the ISO to add the necessary exposure
depending on the mode which is a little more primitive of a method as
compared to the EV adjustment, but I like it.
All in all, I've been able to make it work, but it is irritating, and now
hearing the other users who have had the same experience, I definitely think
someone at Sekonic should be flogged for this. Generally, anyone who would
adopt hand held metering is looking for precision in their photography
exposures and lighting ratios.
I'm going to double check the flash metering on a roll of E-6 and see if
maybe the problem exists there too.
Glenn de Souza
Scottsdale, Arizona
Alan Browne <alan....@videotron.ca> wrote in message
news:3BD6BC68...@videotron.ca...
jufe...@gmail.com
Does any one knows what means E 5?
I really appreciate an answer...
neto...@yahoo.com .mx
Alan Browne
> I have a Sekonic zoom master 508, and it is not working any more...
>
> Does any one knows what means E 5?
>
> I really appreciate an answer...
--
"Political correctness is a doctrine, fostered by a delusional,
illogical minority, and rapidly promoted by mainstream media,
which holds forth the proposition that it is entirely possible
to pick up a piece of shit by the clean end."
-Unknown