No Light Meter

mkiernan · Mar 29, 2007

I have recently purchased a Bronica SQ-A with standard waist-level viewer, and hence no internal light meter. I assumed that as I do not have a light meter that I could use my 35ml camera (Pentax MZ-50) instead until I can save up enough to buy one. Thus I set the Sigma zoom lense to 50, standard on the 35ml SLR, to approximate the 80ml lense on my Bronica (standard of 6x6 MF). Determined the exposure I wanted on the 35ml and transfered this to the MF. However the negatives, when I developed the file (HP4 in HC110) were excessively over-exposed.

Is anyone able to explain to me why this occured. More importantly, can anyone explain how I can use my 35ml camera, with internal light meter, as an interim light meter for my Bronica until I can afford to buy a proper meter?

Thanks
Michael

Nick Zentena · Mar 29, 2007

Is the zoom constant aperture or variable? If it's variable did you check the actual aperture?

David H. Bebbington · Mar 29, 2007

Did your Pentax have film in it? If not, its meter would have defaulted to ISO 100 (assuming you did not have any film speed correction dialed in).

Regards,

David

Mark_S · Mar 29, 2007

Try shooting a roll outdoors using the sunny 16 rule, always the same exposure but a variety of different shutter speed/aperture combinations as a sanity check on both the shutter and aperture. For grins, use the same film/exposure settings and do the same with your Pentax MZ then process the films together, see if they look similar....

BWGirl · Mar 29, 2007

Michael, pm me with your email address & I'll send you a Word file with my full set of "Sunny 16" rule cards. I have a set for all 'sun' conditions and most major film types. I print them out & cut them to size & seal them in clear contact paper. They end up being close to 4"x7".
Let me kn ow if you want them!

wirehead · Mar 29, 2007

You may need to apply a correction factor between the two cameras. Try doing a bracketed sequence.

All of my medium format shots are done using either a digital P&S camera or my ancient Canon SLR.

Peter Black · Mar 29, 2007

mkiernan said:
I have recently purchased a Bronica SQ-A with standard waist-level viewer, and hence no internal light meter. I assumed that as I do not have a light meter that I could use my 35ml camera (Pentax MZ-50) instead until I can save up enough to buy one. Thus I set the Sigma zoom lense to 50, standard on the 35ml SLR, to approximate the 80ml lense on my Bronica (standard of 6x6 MF). Determined the exposure I wanted on the 35ml and transfered this to the MF. However the negatives, when I developed the file (HP4 in HC110) were excessively over-exposed.

Is anyone able to explain to me why this occured. More importantly, can anyone explain how I can use my 35ml camera, with internal light meter, as an interim light meter for my Bronica until I can afford to buy a proper meter?

Thanks
Michael

A couple of considerations. First would be to check the battery in the SQA to make sure it is OK and not liable to be the source of any problem. The second would be to look into the SQA lens and make sure it was actually stopping down when you fire the shutter. The third would be to switch the Pentax to manual metering and focus. I can't see why that should make a difference, but these are all cheap/free items to check before going any further.

There is an item on dry firing the Bronica on the link below, along with other tips/problems.

http://www.camerahobby.com/Photo-Bronica_Tips.htm

removed account4 · Mar 29, 2007

BWGirl said:
Michael, pm me with your email address & I'll send you a Word file with my full set of "Sunny 16" rule cards. I have a set for all 'sun' conditions and most major film types. I print them out & cut them to size & seal them in clear contact paper. They end up being close to 4"x7".
Let me kn ow if you want them!

great suggestion!

i only use a meter when i am on assignment, otherwise
i judge light and use sunny 11, after about a year i have gotten
as good or better than my meter.

john

maxbloom · Mar 29, 2007

In my experience, this occurs because of a combination of field of view and average metering on the part of the 35mm. Approximating lens lengths doesn't necessarily do the job. While a 50mm lens on a 35mm camera is roughly approximate to an 80mm lens on a MF, the field of view still differs greatly by format size; i.e. although the lenses are roughly equivalent, the overall field of view is going to change greatly between 645, 66/67, and 69. The field of view of your 50mm lens is much closer to an 80mm on a 645 than on a 6x6. This was the problem I experienced when trying to use my ME Super to meter for my 6x9 graflex. Essentially, if the 35mm meters for a particular subject (this is especially true outdoors) and averages the metering, it's going to overexpose because the wider field of view on the 6x6 will let more light in. I would suggest that if you want to use your 35mm to meter for the Bronica, then switch to a wide-angle lens.

jimgalli · Mar 30, 2007

You're assuming the shutter on your Bronica is working perfectly. It may not be. Lots of variables here. But your thinking is sound. When I first started in medium format with my Mamiya Universal I bought a twin camera platform and the Mamiya was sitting on the same tripod as the Nikon. I'd meter the chromes with filters and all and usually also take the photo with the Nikon, then I'd put the filters on the Mamiya and have it simply do the same as the Nikon did. Shot lots of good Velvia that way.

Ole · Mar 30, 2007

Even on a fixed-aperture zoom lens, there can be considerable difference between the f-stop and the light transmission. The f-stop is a mathematical aperture, which is not corrected for light loss in the lens. The Bronica lenses are simpler in construction than zoom lenses, and transmit more of the light.

I wouldn't have thought that the difference could be enough to cause significant over-exposure, though...

You could see if you can find a cheap fixed 50mm lens for the Pentax, that would be closer to the Bronica lens in terms of light transmission.

mkiernan · Mar 30, 2007

Thankyou to everyone who replied to my posted question. There were many useful suggestions and offers of help. I will probably try the estimation approach first as I now realise that there may be too many variables to sort out in trying to calibrate two cameras. Given I do ultimately intend to purchase a light meter some day, it may be best to wait until then as I will probably need to run a few tests to get these to interact reliably.

Thanks gain.

Michael

Ulrich Drolshagen · Mar 30, 2007

Hi Michael,

sunny 16 is really a viable approach but I'd as well look at a well known auction site for an old Weston Master V. Examples still in working condition go for a song there. So for a shiny new one you can wait till christmas then ;-)

Ulrich

haris · Mar 30, 2007

As prices of secondhand meters can be as low as 5 to 10 EURO, there is no reason not to buy one...

jrydberg · Apr 11, 2007

haris said:
As prices of secondhand meters can be as low as 5 to 10 EURO, there is no reason not to buy one...

But what kind of meter is that?

I do not want to have to run over to the objective and read the light, esp if I shoot landscape . The closest to a handheld spotmeter must be a SLR or DSLR.

Ulrich Drolshagen · Apr 11, 2007

jrydberg said:
I do not want to have to run over to the objective and read the light, esp if I shoot landscape . The closest to a handheld spotmeter must be a SLR or DSLR.

If you are not one of the zone system guys, there ist no need for a spotmeter. You can get away with simple object or incident light metering generally.

Ulrich

Frank R · Apr 11, 2007

jrydberg said:
I do not want to have to run over to the objective and read the light, esp if I shoot landscape

No running needed. The sun falling on distant mountains is the same falling on your head. It will provide the same reading on an incident meter. If you are shooting into shadows you can step into nearby shade. Its not hard and it works remarkably well. An incident meter is pointed back at the camera from the subject not at the subject like a reflective meter.

I recommend looking for a Norwood Director.

No Light Meter

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