ETTL problems with MP-E + MT-24EX?

Hi,

I just bought a MP-E lens and MT-24EX flash off a forum member. I am using them with a 40D. I have been trying for the last 2 hours to get the auto-exposure ETTL functions on the flash to work--but no matter what I do, every shot is way over exposed (near white). Please help!--I've tried everything:

1. -3 compensation on the flash or -2 on the camera brings the exposure closer, but still over exposed.
2. I've tried orienting the flash heads around the ring with no change.
3. Changing the angles of the heads do not help.
4. "ETTL" does show on the flash's display. I made sure the compensation on the flash is also at 0 (or - when testing).
5. "P" mode on camera, or auto macro setting. 0 exposure compensation. Auto ISO. "Evaluative" metering set for flash from settings menus. I think pretty much everything is auto that I can find.

I have a 580EX II that I've used with the same settings, and never had problems. Any suggestions?

Thanks,
Dean

anyone?

Try removing the flash, cleaning the contacts, and when reattaching it make sure it's fully and correctly in the shoe. I know it sounds petty and basic, but the only time I've had trouble with flash doing what you describe was because one of the contacts was not connected properly.

PS - have fun with that awesome rig

Try shooting in manual mode. Who knows, that might help.

Xyclopx wrote in post #6231256
Hi,

I just bought a MP-E lens and MT-24EX flash off a forum member. I am using them with a 40D. I have been trying for the last 2 hours to get the auto-exposure ETTL functions on the flash to work--but no matter what I do, every shot is way over exposed (near white). Please help!--I've tried everything:

1. -3 compensation on the flash or -2 on the camera brings the exposure closer, but still over exposed.
2. I've tried orienting the flash heads around the ring with no change.
3. Changing the angles of the heads do not help.
4. "ETTL" does show on the flash's display. I made sure the compensation on the flash is also at 0 (or - when testing).
5. "P" mode on camera, or auto macro setting. 0 exposure compensation. Auto ISO. "Evaluative" metering set for flash from settings menus. I think pretty much everything is auto that I can find.

I have a 580EX II that I've used with the same settings, and never had problems. Any suggestions?

Thanks,
Dean

I've never used "P" mode for macro but it may be a case where your flash is simply too close to the subject and it can't fire a blast at a low enough power given that in P mode the camera may be allowing in way too much ambient light. In essence you may be telling the camera to balance ambient with flash but the flash is so close to the subject and the shutter is staying open so long that way too much light is hitting your sensor and blowing out your image.

Again, I'm kinda guessing as I don't shoot macro in P mode. I honestly find it much easier to shoot in Manual mode with my MT-24EX and my 100 macro plus extension tubes.

Switch to M. Stop down a bit...6.3, 8, etc....set shutter speed to your cameras max sync speed (probably 1/200 or 1/250) and try again with your flash in ETTL and flash exposure compensation set at 0 to start. Keep ISO low too. Basically you want to see the little indicator needle on your cameras meter pushed all the way to the left. If ISO is too high then you may allow ambient light to creep in and influence your exposure.

This way you probably won't be allowing in any ambient light to contribute to the exposure and blow it out and the ETTL can do it's thing and expose the subject properly.

Also, as suggested above clean the contacts on hotshoe and flash .
Good luck!

Thanks guys for all the advice. Yeah, for now it seems manual mode is the way to go--I haven't had time to try, but I'm sure manual mode will work perfectly. Both flash and camera work, so it's surely a matter of exposure control.

I took the whole setup to Samys (a local pro camera chain) and the dudes there checked it out and didn't find anything wrong with how I made the settings. I also made sure I cleaned all the contacts well--and sure enough, when they tried shooting with it, once again everything was way overexposed. Funny, the guy even snapped his head back and said, "Whoa!" He mentioned that when he used that lens, he always used manual mode too, and never tried P or any of the other automatics. So, he briefly checked the web to see if that lens is fully ETTL compatible, but didn't find anything, and they were closing so we left it at that.

Does anyone know if the MP-E is compatible with ETTL? That might be the problem. The shop dudes conjectured that since this was Canon's sole manual-only lens, it might not even be supplying data needed for ETTL.

Although I find it really strange that the manual for the flash has specific notes for this lens, and also even mentions how easy the flash is to use in ETTL + P (or other auto modes), and never mentions such problems I'm having.

There's got to be something wrong with the flash...send it back to that hoser who sold it to you! LOL

I used it in E-TTL every time w/ the MP-E. Can't post anything up b/c I'm at work but like I said before. Flash in E-TTL, camera in M: 1/250, f/11, ISO 100 and if you're still getting white frames, something's broken.

Guess I'll found out what the problem is soon enough!

AFAIK every lens is E-TTL compatible. They're independent. The camera just uses the lens to get the exposure.

Anyway, I have the MP-E and only ever use ETTL so it's not the lens. Have you tried other lenses with the MT24EX? Same result? Have you tried other flashes with the MP-E? Same results?

Have you set both the camera and the flash FEC to 0? You know you can set it on both, I believe one overrides the other?

You now have the finest dedicated macro lens with probably the finest macro dedicated flash, don't waste all that using automatic settings that take the control away from you. Shoot full Manual and learn how to control the camera

Start with settings scot079 suggested above and take it from there. For more background in darker lighting conditions, maybe up the ISO to 200 or 400, or slow shutter a little to 1/200 or 1/160 min. Make sure both your camera FEC and flash FEC are set to 0 as a starting point. If you're shooting with those settings and everything is coming out way overexposed, something wrong and get it fixed.

ah, okay... thanks for clarifying the lens + ettl thing.

actually, i did try my 580exii with the lens briefly. wasn't a very good test as i didn't have an off-shoe cord, but it did "seem" to work correctly.

i don't have any other lenses that the mt24ex can attach to, so no, did not try other lenses with that flash.

as for FEC, is that the exposure compensation?--sorry, forgot what that was. cause i kinda remember seeing FEC on my camera's menus, but it was greyed out or something. i was only able to adjust the compensation. as i indicated, both camera and flash were set at 0.

and yeah, if i shoot manual, i'm sure i can get adequate exposures (though i haven't had time to try)--either lowering ISO, or shortening the shutter time, or decreasing the aperture. my question is specifically about the auto modes though. the manual specifically says that this flash is fully automatic, (apparently with specifically the MP-E,) if need be in "P" and "A" modes, and other auto modes.... and that is my question--is the manual wrong?

troy, can you do me a favor and try setting everything to 0 / auto? that is auto iso, awb, 0 compensation on both camera and flash, and Program shooting mode? do the pictures come out exposed okay? if it comes out way over exposed, then i guess that's the way it should be.

FEC is the second button from the right on the strip on top of the 40D IIRC. It's the flash icon with the +/- next to it (in a small box).

I would assume that in P or A modes, it will be opening up the aperture too much for the flash's lowest output. Try shooting ISO100 in M with a variety of apertures, and see if the flash is adjusting exposure each time to a similar value each shot.

Off-shoe chord shouldn't affect the test. If the 580 exposed correctly with the MP-E, you can safely rule out the lens as the problem and focus on the flash.

You shouldn't need to attach the MT24EX to a lens, that won't affect the test. I'd just handhold it somewhere near where it would be if it was attached.

FEC is flash exposure compensation. This is different to EC exposure compensation, which I suspect is what you're referring to on your camera's menus since I set it not through the menus but with the buttons on top display buttons of my 30D. It's a little flash lighting bolt with +/- next to it. When set to 0 it shouldn't appear on the display on top of camera. If it's set, you'll see the bolt +/- icon.

I don't have the MT24EX, but on both my 430 and 580 you set FEC by hitting the set button then + or -. Again, if it's set to 0 no icon is displayed, but if it's set you'll see a bolt and +/- icon in the flash display. Hope that helps.

As for shooting auto modes, I have no idea. I have never used them, ever, on my camera. I'm fully manual baby

Don't have my gear with me at the moment. Will have to try later, but I'm going out tonight so will be over the weekend some time. Maybe someone else can confirm/test in the meantime.