Using *istD with standard TTL flash

I have asked about this on a couple of other forums without finding an answer , was directed here , and have read through Matt's helpful guide before posting this .

Using *istD with standard TTL flash
One night recently , I was toying around with some kit I hadn't used in a while .

Amongst other things , my *istD and the Metz 70 MZ-5 flash . Now that flash goes back to film days , and does not support P-TTL , but it always used to work fine via standard TTL , which the *istD also supports . At the moment , the Metz triggers , but discharges at full power , thus wildly overexposing . The flash ready display in the finder continues to flash even after the flash is ready , and it will not set shutter speed for flash . This is with the SCA 3702 adapter .

By contrast my Metz 54 MZ-5 works perfectly with the camera every time , as well as with my K10D .

The 70 still does not work properly using the SCA adapter from the 54 ( SCA 3702 M2) , but both flashes give controlled outputs with both my MZ-S and my LX ( the 54 preflashing with the MZ-S thus also doing P-TTL ) .

I have checked hotshoe contacts for cleanliness , been through all menus on the camera , the flash , checked settings on the SCA adapters - even read the manuals !!!

I like the 70 for it's high output and fast recycling times , so would like to find the answer to this .

The 3702 is the correct adapter - I used it for a long time , also with the 50 MZ-5 I had before the 70 , and both used to work perfectly with the *ist D : this is what is bugging me - it used to work perfectly in standard TTL with that camera and give really great exposures , filling large rooms with a combination of bounce plus supplementary flash .

The later adapter for P-TTL on the 54 MZ-5 is the 3702 M2 ( which I also have and have tried ) .

It just runs in my mind there was a setting on the camera to make it work in standard TTL rather than P-TTL ?? I have tried various manual modes , plus using the aperture rings on lenses as opposed to setting aperture from the body - it was something like that , but I have forgotten .......

I have the feeling I am missing something really stupid and obvious !

If anyone can suggest what I may be missing , I would be grateful .

Glad to see you found your way here, hopefully Matt will be along in due course and have some suggestions that may help.

are you using an "M" lens? or perhaps a bad connection between the flash and the sca adaptor?

I wasn't the other night when I was experimenting : I had a Sigma EX lens on which I had previously used successfully with the flash , and I had tried it both on the A setting as well as using the aperture ring - this was one of the notions that sprung to mind . I do have a fair selection of lenses which have been used with this flash and body in the past .

I had also checked connections both between SCA and hotshoe , as well as between SCA and flash .

Both flashes appeared to work correctly , giving controlled ( ie clearly not full output ) discharges when used with the MZ-S and with the LX , the 54 would preflash on the D and the MZ-S , which it also does on the K10D , indicating P-TTL operation .

It is only on the *istD that the 70 does not seem to operate under TTL from the camera . I have a few other older TTL only flashes up in the attic , including a 32 , a 40 and a 45 , all of which use the older SCA300 system and will try these with the camera when I get a chance .

One common mistake is to leave the red-eye reduction setting on giving the impression that a pre-flash is occurring, when in fact, it isn't, or may not be.

TTL flash employs feedback from a sensor inside the mirror box which measures the light reflected from the film/sensor surface. Could your *istD TTL sensor have some foreign body inside it perhaps?

Can you beg, steal, or borrow an older Pentax TTL flash and try that, say an AF280T or similar?

It is definitely not the red eye reduction mode - I cycled round all modes .

I doubt there is any foreign body present - the mounted lens has not been off the body in a while , but will check for this anyway , thanks .

I do have a couple of old Pentax TTL flashes in the attic , as well as the older Metz ones , I will have a rummage around before long .

Which mode did you have the Metz on?
My 50MZ5 has EM and TTL. I'd make sure it's on TTL mode. I have the SCA3702, not the 2 version. (Was going to sell the Metz as I don't use it these days)
Will try and check if I can find time!!! (And I'll have recharge the Metz too!)
Matt

Both Metz's were on TTL mode , I remember the easy mode on the 50 , but am not sure it exists on the 70 ....

I did go round the various modes on the Metz , having fully reset it as well - this included checking the zoom was set for APS sensor size , tried rear curtain sync on and off ( along with the corresponding setting on the SCA ) , I also had flash bracketing on and off , as well as the main flash head on direct as well as bounce settings and the auxiliary flash both on and off .

Both flashes gave normal , controlled discharges when used on my LX , without changing anything and the 70 similarly gave a controlled output with my MZ-S , while the 54 preflashed with the latter camera . Because both flashes seem to be working as expected with other cameras , I am leaning towards the symptoms being something to do with the *istD
.

I have , in the past , used the 70 on the *istD and it 'just worked' without any fuss or drama .

I have the 3702 module on the 70 and the M2 version on the 54 . I did try the M2 module on the 70 with no change , never tried the standard one on the 54 ....

I am away from home tonight , but will try some other TTL only flashes with the D when I get home .

All of this sprung from a notion that a lot of this kit had not seen any use in a while - two of my three battery packs for the 70 were dead , the third gave only a few exposures ; having cycled them a few times since two have come back but the third seems past it - I will need to get some tagged NiMh cells to repopulate them with .

When I fit a 3402 M6 module onto the 70 , and use it with my Nikon D300 , it preflashes and exposes perfectly , suggesting that it supports Nikon I-TTL , even though the book says it shouldn't . I guess I-TTL is less demanding than P-TTL .

Well , I finally solved the problem , and I can hardly believe what it was !

I took the camera out today , and fired off about 100 shots - a mixture of daylight stuff and a few using the 54 for fill in flash - all of which worked well .

Tonight , when I came home , I decided to have another look at the Metz 70 - I have been very busy all week and had not looked at it since last weekend .

Tried fully resetting the camera - no difference , I was still getting full power discharges , although the 54 gave controlled outputs and preflashed , indicating P-TTL operaton , with good exposures .

After a while , the *istD was showing the 'battery depleted' message , so I replaced all eight batteries - lo and behold , the Metz 70 started working correctly again - I also noticed at this point I was again getting the focus assist beam which had not been coming on up to then ( although I would have expected this to be powered from the flash battery and not the camera battery ) .

Until a very short time before the camera batteries expired , the battery indicator on the camera had been showing full charge ( the batteries were Duracell Procell Alkaline AA cells , and the replacements the same type ) . Because the indicator had been showing the batteries had plenty of power and the camera was otherwise working normally , as well as with the other flashgun , I had not considered them as a possible cause of the problem . In retrospect it now seems an obvious thing that I ought to have checked earlier .

Glad to know you solved the problem.

Alkalines are not the best choice of battery to use in cameras though. Rechargeable cells like Eneloops which have a very low self discharge rate are a far better option.

I have a fair quantity of NimH cells - both standard 'Energizer' and more recently have bought a number of the low self discharge Duracell 'Stay Charged' ones - I find these more useful for flashes where they give faster recycle times compared to alkaline batteries : however for use in cameras , even with 2400 mAh rechargeable AA cells , I find they don't give the lifespan of standard alkaline AA cells ( perhaps due to the extra .25V nominal voltage ) . Besides that , I am supplied with alkaline batteries from work , so always have a decent stock of them .