[MikePerham]

To turn off the preflash you need to set the flash to manual, not the camera. Of course the camera then dosn't know what exposure to use so you have to set that manualy as well.

Regards, Mike.

[Gooneybird]

To turn off the preflash you need to set the flash to manual, not the camera. Of course the camera then dosn't know what exposure to use so you have to set that manualy as well.

Regards, Mike.

OK, tell us how to set the flash to manual. I'm talking about the pop-up flash built on the camera, of course. As I've said earlier in this thread, I already have everything else on manual - aperture, shutter speed, and focus. So- how can I set the flash to manual? Apparently you must be the rare one who knows that this can be done, so help us all.

Thanks, Olin

[Russell-Evans]

There is no way to turn it off. P-ttl preflash will not fire with a fully manual lens, but the flash will only fire at full power. The most practical approach is to get an inexpensive flash with an Auto setting (not TTL or P-TTL) and use that instead.

The on board flash has a guide number of 11 at ISO 100 at full power. At an aperture of 3.5 the maximum distance is about 10 feet. You would need to be at ISO 400, GN 22 for the flash at full power, and f/3.5 to get the 20 foot distance the OP was shooting at. It seems practical to be using the on board flash for this as long as the lens has an aperture ring to me.

EDIT: I read the thread again and I don't know where I got it in my head the OP was 20 feet from the subject. My bad.

Thank you
Russell

[Marc Sabatella]

OK, tell us how to set the flash to manual. I'm talking about the pop-up flash built on the camera, of course.

Move the aperture ring off the "A" position. Only works on lenses with an "A" position, of course. You could also tr the trick of not completely locking the lens into position, although I'm not sure what that would do exactly. Otherwise, you'd need a flash that supports manual operation. Probably any $25 external flash unit would do.

[rogerstg]

The on board flash has a guide number of 11 at ISO 100 at full power. At an aperture of 3.5 the maximum distance is about 10 feet. You would need to be at ISO 400, GN 22 for the flash at full power, and f/3.5 to get the 20 foot distance the OP was shooting at. It seems practical to be using the on board flash for this as long as the lens has an aperture ring to me.

EDIT: I read the thread again and I don't know where I got it in my head the OP was 20 feet from the subject. My bad.

Thank you
Russell

You make a good point about calculating manual, and I was thinking along those lines until I remembered that he's trying to shoot hummingbirds. It's tough to get those critters to stay still while I break out my side rule

[dylansalt]

I don't seem to have this problem at all with my onboard flash - only if it's set to red eye reduction.

I have shot on manual, x-sync and auto - full and as fill in-from iso 100-1600asa - non of my subjects look half asleep.

My shot of the Guinea Fowl was shot at 3 foot away with flash - if the onboard flash had given off a preflash - that shot would never had happened.

Is my 10d unique or am I missing something?

d

[MikePerham]

OK, tell us how to set the flash to manual. I'm talking about the pop-up flash built on the camera, of course. As I've said earlier in this thread, I already have everything else on manual - aperture, shutter speed, and focus. So- how can I set the flash to manual? Apparently you must be the rare one who knows that this can be done, so help us all.

Thanks, Olin

Sorry, my remarks apply only to an external flash. The on board pop-up flash can only be used in PTTL, as a trigger (only) to fire an external flash or it can also contribute to the exposure - you choose, and in contrast control mode where it is - 1 EV below an off camera flash that it triggers.

The problem is that the exposure is measured in the viewfinder which is blacked out during the exposure, hence the preflash. In the good old days of film, the LX had a superb off the film exposure reading but unfortunatly there is something about the reflectance off sensors that precludes that approach. And there is no manual mode with the on camera flash ...you will need an external flash (540 or 360 FGZ both have good manual control features).

Mike.

[Gooneybird]

Sorry, my remarks apply only to an external flash. The on board pop-up flash can only be used in PTTL, as a trigger (only) to fire an external flash or it can also contribute to the exposure - you choose, and in contrast control mode where it is - 1 EV below an off camera flash that it triggers.

The problem is that the exposure is measured in the viewfinder which is blacked out during the exposure, hence the preflash. In the good old days of film, the LX had a superb off the film exposure reading but unfortunatly there is something about the reflectance off sensors that precludes that approach. And there is no manual mode with the on camera flash ...you will need an external flash (540 or 360 FGZ both have good manual control features).

Mike.

Thanks Mike for the clarification. You got me straightened out finally, in spite of all the conflicting other answers I now realize this camera does not have a menu item to allow putting the flash on Manual.

Another reason I've been confused is I've been discussing this situation with another hummingbird photographer, who seems to do a far superior job than can I. He is using both a Nikon D50 and D300, with the same Sigma 180 mm Macro lens that I have (except for the different mount, of course.) It is now clear that those cameras DO have a manual selection in their menues, and also can change the power output of the on-camera pop-up flash. Something the K10D lacks, in both cases. Oh well, guess that's my tough luck, I've got too much invested in the Pentax gear to switch now. That leaves me with the choice of buying an off-camera flash for mounting on the hot shoe.

Once again, thanks for clearing this up for me.

Olin

[Marc Sabatella]

Thanks Mike for the clarification. You got me straightened out finally, in spite of all the conflicting other answers I now realize this camera does not have a menu item to allow putting the flash on Manual.

Note my last answer is *not* in conflict with this. There is no *menu* to put the on-board flash in manual mode, but putting the lens aperture ring (if it has one) anywhere other than "A" *does* force the flash the fire at full power. Meaning you can use the standard aperture / distance / guide number formula to control exposure.

[HGMonaro]

That leaves me with the choice of buying an off-camera flash for mounting on the hot shoe.

which IMO, would/should be you next aquistion anyway... much better/powerful than the onboard flash. Do you ever get shadows from the lens combined with the onboard flash?

Nige.

[Gooneybird]

Move the aperture ring off the "A" position. Only works on lenses with an "A" position, of course. You could also tr the trick of not completely locking the lens into position, although I'm not sure what that would do exactly. Otherwise, you'd need a flash that supports manual operation. Probably any $25 external flash unit would do.

Just to be sure, I tried the above on two different lenses. Both new designs, one almost brand new. Guess what? When I moved the aperture ring off the "A" position, the camera refused to work at all!!! This was the result with both lenses. Not the best advice, as I see it.

[Gooneybird]

Note my last answer is *not* in conflict with this. There is no *menu* to put the on-board flash in manual mode, but putting the lens aperture ring (if it has one) anywhere other than "A" *does* force the flash the fire at full power. Meaning you can use the standard aperture / distance / guide number formula to control exposure.

Please see my previous post, which also pertains to this subject. We do not find your solution is workable.

[rogerstg]

I don't seem to have this problem at all with my onboard flash - only if it's set to red eye reduction.

I have shot on manual, x-sync and auto - full and as fill in-from iso 100-1600asa - non of my subjects look half asleep.

My shot of the Guinea Fowl was shot at 3 foot away with flash - if the onboard flash had given off a preflash - that shot would never had happened.

Is my 10d unique or am I missing something?

d

Like you, I have had no problem with people and p-ttl. I got some snitty comments when I mentioned that in another thread.

Although hummingbirds are probably different since they are so quick.

Not in the present situation, but generally, when web surfers write about problems with ttl and blinking, IMO they are confusing red-eye reduction and/or focus assist with the actual ttl preflash.

[Canada_Rockies]

Just to be sure, I tried the above on two different lenses. Both new designs, one almost brand new. Guess what? When I moved the aperture ring off the "A" position, the camera refused to work at all!!! This was the result with both lenses. Not the best advice, as I see it.

You also need to go into the Custom Menu and set [Use Aperture Ring] to [Permitted]. Darned if I know why Pentax would ever need it to be not permitted because mine works just fine with all lenses with it set to permitted.

[Marc Sabatella]

You also need to go into the Custom Menu and set [Use Aperture Ring] to [Permitted].

Correct. And once that option is set, it can safely be left that way. Since that apparently hasn't been done yet, I'm assuming the OP has never used a manual lens on this camera before, so it would also be a good idea to practice doing that first. Most of the online info talks about metering with the green button to stop down and set shutter speed, but of course, that's not what you want here. You'll want to set aperture according to the guide number formula (or whatever experience suggests), and simply set shutter speed to 1/180, or slower if you're trying to get some ambient light in there too.

Darned if I know why Pentax would ever need it to be not permitted because mine works just fine with all lenses with it set to permitted.

I'm assuming it is so people who have lenses with aperture rings that have an "A" position - like the OP - don't accidentally knock their rings off the A position then wonder why their exposures are all off. Instead, they'll wonder why the camera doesn't take the picture at all, which is hopefully an easier thing to figure out. Or maybe not.