working with Sinar Booster1

[Tudor Vreme]

I have a Minolta Flashmetter IV with sinar booster1, I tried to do some measurements on field on the GG but I had big difference between reflective normal reading and the booster.
Is there any documentation detailed about how to work with booster, etc. where can i find it? Sinar doesn't give to much information.
I want to use it for close-ups, architecture readings and sometime for landscape.
usually I work with natural light, but I'm interested to work with flash also specially for close-ups.
thanks,

[aporodagon]

Tudor

The booster meter combo works as a null meter, that is the meter is set to a required shutter speed and to f5.6 (same method works for flash, but the meter is set to flash mode). Deviations from this reading of f5.6 determine how to adjust your aperture. If you were trying to make a direct reading with your meter to compare and not using the null metering method, your readings would be different, as you experienced. If you don't have the instructions for the Sinar probe, let me know. I may have a copy lying around.

John

[Hiro]

Some instruction docs are under "Downloads > User Instructions" at sinar.ch.
Would a short instruction sheet help?
http://www.sinar.ch/file_uploads/bibliothek/k_87_UserInstructions/179_0_boosterminotaengl.pdf.

[Tudor Vreme]

Thanks John, getting information is not so easy where I am, also there are few people in area that work on LF, (3 person including me in Timisoara), and they have a basic equipment. I'm the only one that have a booster at the moment, so no experience to share with. Above this there is a matter with language, because no all the technical terms I can understand.
So every information is usefull.
Hiro, - I downloaded the short instruction sheet, but is not clear for me ( maybe because my english ).

So, is I use the booster as a null metter, I take a reading at f5.6 and a time set of 1s, my metter give me a f11 reading, how I can check is the exposure is correct?
tanks guys for your support.

[Helen Bach]

Tudor,

Method 1 (the Sinar instruction book method): The lens is set to the working aperture, not f/5.6 (unless f/5.6 happens to be the working aperture, of course). The meter is set to f/5.6 (no matter what the lens aperture is) and the time is read. This method measures at the working aperture of the lens, so it takes into account any errors in aperture scale markings and any changes in relative illumination as you stop down.

Method 2 (an alternative way. I hope that mentioning this does not confuse the issue - if it does then ignore this paragraph!): The lens is set to f/5.6 and the meter is read. The meter gives the aperture and time that will be used. This method assumes that the ratio of illumination between f/5.6 and the working aperture is exactly as it should be in theory. It may enable the meter to be used in dimmer light than Method 1 (the method can be simply extended to meter at the maximum aperture of the lens). There may or may not be any point to using this method instead of using a simple non-TTL meter.

Your example:
Lens set to f/5.6, meter reading is f/11 at 1 s. The correct exposure time for f/5.6 would be 1/4 s. You could also assume that the exposure at f/11 would be 1 s, because the lens is set at f/5.6 for the reading. However, if you wanted to use f/11, the most accurate way of using the meter would be to set the lens to f/11 and find the meter reading for f/5.6.

Another example:
Lens set at f/22. Meter reading is 5.67 at 1/15 s. This means an exposure of f/227 at 1/15. If you stop the lens down 2/3 of a stop (ie to f/22 and two thirds) the meter should now read 5.60 at 1/15 s.

You might be interested in John D's page on the Booster 1 etc:

http://www.johndesq.com/pinhole/altdensitometer.htm

Later:
You could do a rough check by pointing the camera at an evenly-illuminated wall (you could focus the camera at infinity) then comparing the reflected reading from the hand-held meter with the TTL reading using the Booster 1.

Best,
Helen

[Tudor Vreme]

Thanks Helen, everything is clear, I'll do some readings and tests today, I'll let you know.
It's diferent from what I understand from Sinar short documentation.

[Tudor Vreme]

Helen, John, Hiro
Thanks for the informations, the tests works OK, and the link is also very usefull.
Both metods works.
Good and reliable informations.
Tudor