Flash Control with m4/3 Primes

[Boatman]

Right after Christmas I posed a thread, Flash Photography, about some issues I was having with a GH2 and an FL36 flash. The take-away from that experience was that the camera and flash combination worked best with the camera in full manual mode with baseline settings of roughly ISO640, f2.8 and 1/100 of a second. The flash should be put in the AUTO mode (not TTL-AUTO), which provides good exposure control and very fast flash cycling, much better than TTL-AUTO.

Yesterday I was messing around with some old 50mm primes and making comparisons between them. Because it was at night, I used the flash. Well guess what? When using a non-intelligent lens, the flash will not allow you to use AUTO mode. Normally there are five options available; TTL-AUTO, AUTO, MANUAL, FP TTL-AUTO and FP-AUTO. This is what I get with either my Panasonic 20mm or 14-140mm lens. However, with any of the primes on m4/3 adaptors the available modes drop to TTL-AUTO and MANUAL.

According to the FL-36 manual, pages 34-35, with a manual camera the flash should work in AUTO and MANUAL modes only. In AUTO mode you set the ISO and f-stop of the camera into the flash and the flash will figure out the rest. In my case, with a half-smart camera, it’s working a bit differently. One would think that with the camera set to manual exposure, the camera flash control would be disabled and the flash would work as with a fully manual camera, but apparently not.

There may be a setting deep in the menus to fix this, but I was unable to find it. Perhaps a hot shoe adapter, passing only the trigger signal, could be used. Has anyone had any similar experience to pass along regarding this? Having taken the time to figure out what settings work best with the flash, it would be nice to be able to actually use them with my favorite prime; still the Takumar 50mm f1.4.

[Shadowman]

Have you checked the Panasonic website for tutorials?

[inkista]

Homer: the more I use the FL-50 with my G3, the more I appreciate my Canon flash gear.

You will not get Auto mode with a manual lens, unless you can find a chip for the adapter ring to fake the electronic communication of the aperture setting of the lens to the body (and I'm just theorizing here. No idea if it would ACTUALLY work). The thyristor (Auto) mode* needs the iso and aperture information to work. This is why we like TTL*. It can work without that, since it's purely metering-based.

But the reason we hate TTL is that it's purely metering-based. I'd check what kind of metering mode you're using if TTL is consistently not working for you, or possibly considering having flash exposure compensation dialed in if the metering is consistently off in one direction when you use TTL. If you default to spot metering, I'd say move to center-weighted or an average/matrix mode instead for flash with TTL.

Why the hell the FP modes kick out without the lens communication, I've got no freaking clue, though, since FP is a shutter-speed thing, and it's not like the camera body stopped talking to the flash. Then again, I don't understand why there ARE FP modes, and why it's not just another setting independent of the TTL/Auto/Manual mode.

If you were using any flash other than an older Olympus FL unit, I'd say just bite the bullet and go into Manual mode. But man, is the manual mode on an older Oly FL screwy. I set the power by adjusting the guide number with handy-dandy distance calculation? Wow, does Olympus really expect you to never use this flash off-camera, for bouncing, or as anything other than your key light. I am super-happy, though, that if I take the thing off the hotshoe completely and use manual triggers, I get the 1, 1/2, 1/4 settings I'm far more familiar with. Just wish there was a custom menu setting so I could make it do that for FP Manual and Manual on the hotshoe, too. [spit]. [update: ah. The FL-600R has such a custom function. Too bad it costs twice what I paid for my FL-50.]

I tend not to like using auto modes on either the flash or the camera, preferring the precision and consistency (and simplicity really) of Manual modes, but then I've been reading the Strobist for too long, and I'm mostly using flash to do stuff like this:


G3, 20/1.8. manual YN-560 el-cheapo flash. bare, held in left hand, triggered with RF-602 triggers.
iso 200, f/16, 1/160s (max. sync speed), YN-560 probably in 1/16 or 1/32 power.

-----
*thyristor/Auto: there's a sensor in the flash that shuts off the flash when the "correct" amount of light has been sensed. Calculations on what's "correct" are based on aperture and iso used.

*TTL: (through-the-lens). The camera tells the flash to send out a "preburst" flash of a known brightness level, meters it, and then adjusts the flash power to what the camera's autoexposure system thinks is a good level.

[Boatman]

Kathy:

I read through the FL manual again this evening and looked at ALL the settings in the GH2 and searched the PDF copy of the manual reading EVERY mention of 'flash'. I should correct my statement about the modes available with manual lenses; only the AUTO is missing, the FP modes are there.

I suppose only having TTL-AUTO available is not such a bad thing, it's just that I just went to a lot of trouble to demonstrate to myself the AUTO mode is significantly better in a number of ways. TTL-AUTO works fine with the manual lenses, you just have to be patient with it. The FL-36 is fully capable of working in AUTO mode with a manual camera, the set up is detailed in the owner's manual. It just does not work the way it is described with the GH2 and a manual lens.

Fabulous photograph, well done!

Shadowman, as for the Panasonic support site, what did you say, a two what? Maybe YouTube

[inkista]

... only the AUTO is missing, the FP modes are there.

That explains that mystery, then.

I suppose only having TTL-AUTO available is not such a bad thing, it's just that I just went to a lot of trouble to demonstrate to myself the AUTO mode is significantly better in a number of ways. TTL-AUTO works fine with the manual lenses, you just have to be patient with it.

Yeah. It's going to be more finicky, but it will still work.

The FL-36 is fully capable of working in AUTO mode with a manual camera, the set up is detailed in the owner's manual. It just does not work the way it is described with the GH2 and a manual lens.

Yeah, sounds like the flash/camera knows what to do with full communication or no communication, but not when it has half the communication.

I ran into a similar issue using adapted MF lenses on my Canons. One of my chipped adapter rings apprently faked being an AF lens a little too well, and the camera didn't go into stop-down metering mode. If I stopped the lens down, the meter would bias as much as I stopped down...(i.e., it thought the lens was still wide open). So, if I was using an f/2 lens, and I stopped down to f/8, then the meter would think I was underexposed by five stops from where I really was. [headdesk]

Adapting manual lenses is pretty much the one thing digital camera manufacturers don't expect us to do.

Fabulous photograph, well done!

Thanks! It actually made me swear a blue streak and convinced me I needed to find an HSS-capable flash for the G3, though. I had to shoot at f/16 to underexpose the ambient and that's a bit too far into diffraction-limited territory for my tastes, and hell, there I was with an f/1.7 lens and a jones for some background blur. But I was already near the minumum iso, and the freaking max. sync speed of the G3 is 1/160s, so I didn't have a choice without an FP mode (or ND filters) to go to. And I didn't want to have to find/buy/carry/stack ND filters and a bunch of step-up rings for my various lenses.

[inkista]

I need to take back something in the advice I gave. I've just learned something about the FL-36.

I said:

If you were using any flash other than an older Olympus FL unit, I'd say just bite the bullet and go into Manual mode. ...

I take this back. I assumed your FL-36 worked the way my FL-50 does. It doesn't. It has the ONE thing I fervently wish for: a custom setting to turn the guide number display off. On pages 47-49 of the FL-36 manual, you can turn off the guide number display. This makes Manual mode hecka easier to use.

Instead of displaying the guide number and distance calculations, you'll get the power ratio. It'll give you the power output setting as a ratio of the flash's full power: 1, 1/2, 1/4, 1/8, or 1/16. You can think of those as stops of flash power, the way that iso 100->200 is a stop or f/2.8-> f/4 is a stop. And adjusting power is simply dialing up or dialing down. Simplicity.

When you do flash photography, you can think of every image as a combination of two exposures combined together: the ambient (all the light that isn't the flash) and the flash (only the light from the flash). And these two, while related are independent of each other. You can choose however you want to balance them.

The key to getting the image you want is in how you balance the two against each other. That flower image that I did underexposed the ambient by 1.5 stops to get the sky to be blue instead of white. Without the flash, the flowers would have been in semi-silhouette. I then used the flash to illuminate the too-dark flowers to bring them up to the level I wanted vs. the sky. The flash can't light EVERYTHING. Just a certain area.

Most of the time, we think of the background of the image as the ambient light, and the foreground subject as the flash (you do have some spillover with the flash, so controlling where the light goes is important, too).

Ambient is controlled, as you know, by iso, aperture, and shutter speed.

Flash is controlled by iso, aperture, flash power, and flash-to-subject distance.

Shutter speed doesn't affect the flash exposure, because the flash burst is far faster than your max. sync speed. Unless you're in an FP mode, you're going to be using a shutter speed of 1/160s or slower.

So, say that your background is too dark, but your subject is lit correctly. All you need to do is increase your shutter speed.

Say that your background is just right, but your subject is too light/dark. All you need to do is adjust your flash power, or move the flash closer/farther.

Say that you have the background and the subject right, but you want a shallower DoF. Adjust the aperture. Then compensate with the shutter speed/iso (for the ambient) and flash power (for the flash) by as many stops as you opened up. (e.g., if you went from f/8 -> f/4 [+2EV], and you were at 1/4 power, then you need to go to 1/16 power).

[Shadowman]

Shadowman, as for the Panasonic support site, what did you say, a two what? Maybe YouTube

Are they that bad with customer support that they can't provide a tutorial? Actually I found this on the website that is partially flash related.

http://shop.panasonic.com/resources/...NT_035631.html

[Boatman]

Well, I wouldn't say they were bad, just insufficient. There really is not much information there and the user's manual is no better. The GH2 is a complex camera and you just have to figure it out.

[Manfred M]

So, say that your background is too dark, but your subject is lit correctly. All you need to do is increase your shutter speed.

I think you have it backwards Kathy. If the background is too dark, you have to increase the exposure by decreasing your shutter speed in order to brighten the background. If you use a faster shutter speed, you'll darken the background even more.

[jcuknz]

I think you have it backwards Kathy. If the background is too dark, you have to increase the exposure by decreasing your shutter speed in order to brighten the background. If you use a faster shutter speed, you'll darken the background even more.

He refers to post #6 to the underlined comment.

The traps of the English language ... I know what each of you mean and both of you are correct, it just depends on how each are interpreting the words

[Boatman]

I take this back. I assumed your FL-36 worked the way my FL-50 does. It doesn't. It has the ONE thing I fervently wish for: a custom setting to turn the guide number display off. On pages 47-49 of the FL-36 manual, you can turn off the guide number display. This makes Manual mode hecka easier to use.

Instead of displaying the guide number and distance calculations, you'll get the power ratio. It'll give you the power output setting as a ratio of the flash's full power: 1, 1/2, 1/4, 1/8, or 1/16. You can think of those as stops of flash power, the way that iso 100->200 is a stop or f/2.8-> f/4 is a stop. And adjusting power is simply dialing up or dialing down. Simplicity.

I missed that part, Kathy, or at least did not appreciate it. Your are right, for balancing your flash and the ambient light, that would be most useful. Thanks for pointing that out.

[inkista]

I think you have it backwards Kathy. If the background is too dark, you have to increase the exposure by decreasing your shutter speed in order to brighten the background. If you use a faster shutter speed, you'll darken the background even more.

I think of shutter speed in terms of period, not velocity . To me "increasing" is increasing the amount of time it's open. Going faster is decreasing the amount of time it's open. But if you're literally thinking of increasing speed as going faster, then yes, my semantics are backwards.

[Manfred M]

I think of shutter speed in terms of period, not velocity . To me "increasing" is increasing the amount of time it's open. Going faster is decreasing the amount of time it's open. But if you're literally thinking of increasing speed as going faster, then yes, my semantics are backwards.

Kathy - we do seem to be saying the same thing.

You've got to love photography; two of the most important settings shutter speed and aperture are hard to explain because of the different ways these can be described.

Shutter speed - the larger the number, the shorter the exposure. the smaller the number the longer the exposure (until you get to exposures greater than 1 second when a larger number = longer exposure). Just to confuse people more, camera manufacturers use the reciprocal of the number. 1000 really means 1/1000th sec, etc..

Aperture - Large aperture number = smaller aperture opening; smaller aperture number = larger aperture opening.

I'm glad that ISO has come the standard way of descibing light sensitivity because explaining that DIN film speed as being logarithmic always confused people quite nicely too. Trying to explain that ASA = ANSI = ISO to a oldtimer coming from film can be amusing too.