REVIEWS - Leica SF-40 Flash versus Leica SF-64 Flash

SIZE AND WEIGHT

I occasionally use the Leica SF-40 and Leica SF-64, so this article is a casual comparison of the two flashes. The main difference between these two flashes is output power, with the Leica SF-64 providing ~40% more output relative to the Leica SF-40. With power comes a heavy price - the Leica SF-64 is roughly 2X heavier and roughly 2X taller. A Leica SF-64 is too large for a Leica M body. The Leica SF-64 flash is more in-scale with the Leica SL Typ 601; however, the overall package is 2685 grams - almost 6 pounds!

USER INTERFACE

The Leica SF-64 has a big sexy touch screen. It is a bit showy, but informative. With the Leica SF-40, much is done on the belief the flash and camera will do the right thing. For example, there is no visual cue as to whether or not the flash is in High Speed Sync (HSS) mode or what focal length the flash has zoomed to. In contrast, the Leica SF-64's rear display shows all the information, so no guessing needed.

On the other hand, the Leica SF-40 is direct with no menu diving or touchscreen taps. Want TTL mode? Okay, just turn the dial to TTL and adjust in the amount of FEC desired. My biggest niggle with the Leica SF-40 is not knowing whether the flash has entered HSS mode or not. A simple firmware change like a steady TTL light (on the rear control) to indicate TTL and the same LED rapidly blinking to indicate HSS TTL would be nice. I do not worry so much about whether the flash has zoomed to the correct focal length, I just assume it has.

OFF CAMERA USE

Wireless flash capabilities have advanced considerably. Nowadays Canon, Nikon, Sony, etc. have a wealth of hot shoe based wireless commanders with TTL capabilities to control multiple flashes. But not Leica... The SF-40 and SF-64 can be triggered by the flash burst of the on-camera flash. Or, they can be triggered wirelessly by a Yongnuo RF-602N set-up. In either case the flash output power has to be set manually and there is no TTL or HSS mode.

After some experimentation, the Nikon SC-17 TTL Cable (now discontinued) proved the most reliable and flexible option for off-camera flash. The Nikon cable is MUCH cheaper than buying Leica's Multifunctional Handgrip M and Leica SCA Adapter Set for Multifunctional Handgrip M. That duo costs over $1000 (at retail) vs a used Nikon cable for ~$20 from Ebay. I did try the current Nikon SC-28 TTL Cable. The contacts did not line up well and it worked intermittently at best. I also dabbled with the Nikon SC-19 Extension Cable and AS-10 Hot Shoe Adapter. Used in conjunction with the Nikon SC-17, this set-up adds ~12' feet of extension cable. Unfortunately, I could not get this set-up to work. So my $.02, stick with a used Nikon SC-17 TTL Cable and don't tempt fate.

POWER

Both flashes require (4) AA batteries. I use Panasonic's Eneloop Pro AA Rechargeable NiMH Batteries, rated at 2550mAh. These batteries have held up well thus far (had them a year or two now). Before I was using Ansmann 2850 mAh batteries, but they stopped taking a full charge after a year of use and became very unpredictable. Generally, I get ~300 clicks out one charge of the Eneloops.

LIGHT QUALITY

Flash guns like these are not known for their warm, soft, lovely light. In my experience, dialing up the ISO and easing off the flash output goes a long ways towards softening the look. I would be hard pressed to say whether the SF-40's or SF-64's output is better; though, the SF-64 has alot more horsepower. The SF-64 also has a larger reflector, so its output seems broader.

Leica's TTL performance… sucks… it is on par with a random number generator. I have tried to tame the output by going pure manual mode, but in M on the Leica M camera, neither of these flashes will go into high speed (HS) TTL mode. Yes, I have raised these issues to Leica - and it has been radio silence. Yes, I have had some successes with Leica flashes, but it has been battle.

I have given up on Leica's TTL, and usually put the camera in M mode and throttle the ISO and flash output until I get an exposure balance I like. This trial and error approach takes ~5 shots to get a scene dialed in. For more on the Leica SF-40 with the Leica M Monochrom Typ 246, check out this post from earlier this year.

CONCLUSION

If planning to occasionally use a flash, the Leica SF-40 is probably a good choice. It is really difficult to make a recommendation because Leica's TTL performance feels random on a Leica M. My suggestion - buy the flash from a store with a very easy return policy.

June 30, 2021 Update - The above article was written in 2018 with the Leica M-246, fast forward to June 30, 2021 and with the Leica M10 Monochrom, flash performance seems improved. For example, I can trigger the flash in manual mode with a shutter speed of 1/500th. More testing is needed, but so far initial testing seems better. I'll update this review later this summer after I have had more time to thoroughly test the Leica SF-40 with the Leica M10-R and Leica M10 Monochrom.