Archived posting to the Leica Users Group, 1999/11/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]In a message dated 11/18/99 4:16:07 PM Eastern Standard Time, imxputs@knoware.nl writes: << Non-TTL test: 3 apertures: 2.8 and 5.6 and 11. On the test equipment the flash output at 1 meter distance 1/3 stop underexposed 2 meter distance OK, but the f/11 was far off (beyond the GN of 20!) 4 meter distance is was OK till f/4. That is 5.6 was beyond the GN reach. The SF20 is very sensitive to this: just beyond maximum range the output drops dramatically. The TTL version gave at 1 and 2 meter distance results 1/3 to 1/2 stop underexposure. The f/2 position however gave a 2/3 stop overexposure. The 4 meter position worked till f/4. >> Questions: 1. What "test equipment" was used? If a flashmeter was it an incident or reflected reading? (An incident flashmeter will differ as much as 1 stop up or down from an auto-sensor or TTL flash that reads reflected light, depending on the subject.) 2. What ISO was the test made at? (We need to know that to interpret the results). 3. Doesn't the SF20 and/or the M6TTL have some kind of an indicator LED which advises when the flash has fired at either minimum or maximum output and over or under-exposure (respectively) has still occurred, thereby alerting the photographer to the need to choose another aperture, distance or film speed? If so, was it saying "good exposure" even though the exposure was "off"? 4. Have you tested that the M6TTL's TTL flash system is accurate with other flashes so as to be certain the discrepancy is due purely to the SF20's electronics? I've been thinking about one of these little flashes but it doesn't sound like it works as accurately as my off-brand pee-wee auto-flash I got at a swap meet for $5 :o( DT