Leica SF20 vs 24D on M10 - A mode pre-chosen f-stops vs TTL

[SOHODE]

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Hi everyone, I have a basic question and hoping you can answer. Is it possible to use SF20 on M10 and control the flash power manually? I know on A mode it has 3 pre-chosen f-stops but can you explain how it works? Does it do the job for street photography? How about the Manual mode? Doesn't it give more control on the flash power?

I know SF24D works TTL but the prices are getting insane! SF20 is more affordable and it's the same size so I'm wondering if I can get it used instead with a bit more effort. But if there are other options that work TTL with M10 please recommend.

Thank you

 

[Tom Johnston]

curious minds want to know, even though I haven't been using flash much these days.

I too have the SF24 (that I used with my M7) but have been reluctant to put it on a digital M even though I've heard it would be okay and not be problematic with regard to the (I'm blanking on the term) strength of the voltage.

 

[SOHODE]

4 hours ago, Tom Johnston said:

curious minds want to know, even though I haven't been using flash much these days.

I too have the SF24 (that I used with my M7) but have been reluctant to put it on a digital M even though I've heard it would be okay and not be problematic with regard to the (I'm blanking on the term) strength of the voltage.

 

Interesting! Is this strength of voltage also the case for SF20?

[Tom Johnston]

Embarrassing…I just noticed my typo. My experience is with the SF20.

 I don’t remember the flash voltage of it either. There was a pretty comprehensive list of voltage ratings for different units from different manufacturers. If I can find it I’ll post a link or what the vol rating is.

 

[charlesphoto99]

According to our own forum advisor Jaap, the M240 and previous digital M's were rated up to 600V for the flash - not sure why that would have changed with the M10 or 11. From what I've garnered, the SF24 is in the 7v or less range. If I can find batteries for it I can test it on my M10-R, though I know it worked fine on my M10 and M9, it's just that I haven't used it in awhile. 

 

 

[jaapv]

https://www.botzilla.com/page/strobeVolts.html

[charlesphoto99]

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The SF-20 is based on the Metz 34cs-2, which according to one user online has voltage of 4.7v. I can't find batteries for the 24 or I would test it with a multimeter (and on camera). 

[olgierdc]

I have two Flash SF 24D. I measured the voltage on both, which the meter usually shows 4.6V. However, if I measure the peak voltage, it is up to 20V (usually between 15-20V).

Used multimeter - Fluke 87V.

[SOHODE]

So It should be safe to use 24D on m10 I think? Has anyone tried it? or anyone has reported any problem?

Also is 24D a  Metz flash?

Thank you guys

[RexGig0]

The brief test-firing I have done, with an SF 24D, did not damage my M10 or M Type 246. 

[olgierdc]

The value of the measured voltage is partly due to the duration of the flash and the duration of the electrical pulse. When measuring the peak voltage with a Fluke 87 multimeter, the voltage pulse time must be greater than 1/4000s because the multimeter needs 250us to measure. The lamp itself has a flash time between 1/250s and 1/30000s. Longer flashes are obtained by using more flash power. So if anyone measures the voltage with a flash shorter than the time in which the voltage measurement is made, they will receive undervalued values. Therefore, I obtained voltages of several volts when measuring with low power or in the non-peak voltage measurement mode. For such measurements, it is best to use a fast oscilloscope with memory. I would consider the 20V voltage results as reference for this Flash.

I am using flash SF24D with M10 and M10-R without problems.

Edited November 17, 2022 by olgierdc

[drew.saunders]

I have an SF20 that I bought years ago to go with my M6 TTL. I just put in fresh CR123 lithium batteries and tested it on my Fuji X-E3, which is as modern as my cameras get. If anyone wants to give me an M10M for more thorough testing, I’d be happy to take it off your hands! 😜

Anyway, it fires just fine without harming the camera in M and A modes. In Manual mode, you can adjust the power in 1/2 stop increments, but instead of giving you fractions of full power, like my Yongnuo flashes do, it shows power as f-stops. I didn’t test this thoroughly, but I have used it as a tiny fill flash with a remote sensor.

 It works fine in Automatic mode, which uses a little sensor on the front of the flash, what my Vivitar 283 called “auto thrystor (sp?).” You can choose f/2.8, 5.6 or 11 only, which you then match on the lens, and you have to match the ISO on the flash to the camera. The two quick shots I tested seemed properly exposed. Sine the camera and flash don’t communicate, you can tweak the exposure easily enough by setting the aperture “off” by a small amount.

There are probably other auto flashes out there that are cheaper, but it is a pretty decent flash.

 I doubt any flash made after 1990 is going to have the high voltage of very old flashes.

Drew