[pathdoc]

The camera arrived in the mail today. It seems to function well, and when I put my AF080C on the camera and take a picture the flash discharges; however, it does not appear to recognise the presence of said flash. As in, when I have the flash mounted and turned on, the P mode is selecting a wide open aperture and a very slow shutter speed as if the flash were not there. I had every reason not to think it was the flash, as a picture I took with my Super Program came out well (all the right TTL things switched on).

The flash works (albeit not in TTL mode, of course) on my K-5.

I unfortunately do not have a second flash immediately to hand that I can try out.

I would appreciate knowing if I'm doing something stupid (or failing to do something sensible) before I consider sending this thing back for a refund (though I will certainly put my AF280T on it tonight and see what happens before I consider that). But shooting in full digital TTL was the reason I bought this thing.

ETA: As soon as I typed these words, it began to work and to recognise the flash. Several test shots at random apertures seem well exposed. Then I switch the camera off to put an M42 lens on and see what happens, and lo and behold it misbehaves again...

Further ETA: And then it works once more.



FOR THE LOVE OF GOD, PENTAX, PLEASE RESTORE TTL PROTOCOL ON FUTURE FULL-FRAME BODIES.

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Last edited by pathdoc; 11-14-2016 at 06:25 AM.

[wombat2go]

Hi Path,
i put the af080c ringflash on the ist ds here. I have the ring mounted on a side flash grip so I can use the AF080c
as an ordinary flash, but at reduced ranges.

In P mode with the flash off, looking at my desk, the camera set the DA lens to
15th and f/4.0, and the green vf flash indicator is flashing.

When the flash is then switched on and charged,
the setting changes to 45th and f/11 , the green vf indicator is steady.
The flash gave a nice exposure.



In the ist ds manual page 153, the right-most column describes available options for the basic TTL flashes
although the AF080c is not mentioned.
Note that the iso settings are limited to only 200 and 400 with TTL flashes.

With a non-A lens, the only allowable mode is M, and TTL works here too.

Hope this helps your P mode diagnosis.

[pathdoc]

I can't explain exactly what happened - it seems to have woken itself up or something and is behaving now. (Touch wood.)

Bizarre as this may sound, I think my K-5 risks becoming a shelf queen (except for wet-weather work) and the K-1 a non-event.

[wombat2go]

it seems to have woken itself up

It is probably contact contamination on these vintage items.
When I got my AF080c out this morning to check your post, it would not switch on until I moved the slide switch on and off a few times.
At halloween I was using an even more vintage flash, Pentax AF160, on the RB67, and lost a few exposures due to intermittent flash.

[pathdoc]

It is probably contact contamination on these vintage items.

As far as the AF080C is concerned, it gets regular use on my K-5. So the whole mounting-and-firing thing is very recent. There may have been an issue in-camera with whichever contact moderates the TTL protocol.

[stevebrot]

In the ist ds manual page 153, the right-most column describes available options for the basic TTL flashes
although the AF080c is not mentioned.

There may have been an issue in-camera with whichever contact moderates the TTL protocol.

#pathdoc, I will go out on a limb here since I own neither the AF080C nor the *istDS. I am pretty sure the AF080C is analog protocol TTL (two extra contacts on the shoe) and I am also pretty sure that the *istDS supports digital protocol TTL (three extra contacts) only. The flash should support a decent level of dedication on the *istDS, but no TTL.

Edit: I feel the branch breaking!!! Thanks to pathdoc and wombat2go for setting me right (see comments below) before I fell and broke my can.


Steve

[pathdoc]

I will go out on a limb here

I think you'd better scuttle a little closer to the thicker part of the bough, LOL - I've been shooting all afternoon at various apertures with both the AF080C and an AF280T, with a Super Tak lens, what is more, and it's all been coming out nicely (except when I try to do bounce flash at ISO 200 and f/16 on distant-ish subjects, but that's hardly the fault of the TTL protocol; the flash just isn't up to that).

Also: https://www.pentaxforums.com/camerareviews/pentax-ist-ds.html

[wombat2go]

Steve, Yes, the AF080c only has the 2 aux contacts to rear of the centre one.
To check whether TTL is working,
I put the SMC Pentax 1:2 55mm on the ist ds , and set the camera to M mode.
Then at f/11 and 180th, I took 3 exposures with the flash in Manual Full, Manual 1/4 and then TTL Auto.
All exposures were at different levels, with the TTL Auto being in between the 2 Manual ones.

The flash has a green light on the rear that flashes when a good exposure is measured.
So I took a succession of exposures: .. f/2.8.... f/5.6....f/8... f/11

The first 3 resulted in a green light, the exposures look OK, and the histos are similar
The f/11 did not show the green light, and it was underexposed. ( The Guide number is 8 in TTL mode)
So with all that I conclude the af080c and ist ds will work in TTL mode.

[stevebrot]

I think you'd better scuttle a little closer to the thicker part of the bough, LOL - I've been shooting all afternoon at various apertures with both the AF080C and an AF280T, with a Super Tak lens, what is more, and it's all been coming out nicely (except when I try to do bounce flash at ISO 200 and f/16 on distant-ish subjects, but that's hardly the fault of the TTL protocol; the flash just isn't up to that).

Also: Pentax *ist DS - Pentax K-mount DSLRs - Pentax Camera Reviews and Specifications

Yep! Better move closer to the trunk!

It had been my impression that analog TTL support ended with "crippled" mount, but the *istDS manual clearly lists several analog TTL flashes so they are obviously supported.

Out of curiosity, do you have TTL support for K and M-series lenses in M mode?


Steve

[wombat2go]

Out of curiosity, do you have TTL support for K and M-series lenses in M mode?

It appears so.

I put the SMC Pentax 1:2 55mm on the ist ds , and set the camera to M mode.

[stevebrot]

Out of curiosity, do you have TTL support for K and M-series lenses in M mode?

I put the SMC Pentax 1:2 55mm on the ist ds , and set the camera to M mode.

Well, I guess that answers that question too. I think I can see why some of our long-time users are so fond of their *istD-series bodies.


Steve

[stevebrot]

It appears so.

You beat me to it.


Steve

[pathdoc]

The big frustration for me is that the uncrippled mount only just failed to survive into the DSLR era; even the MZ-S's mount is crippled IIRC, and probably so too would the MZ-D have been. A DSLR, even an early 6MP CCD one, with an uncrippled mount and full TTL protocol would have been a thing of beauty.

TTL clearly works - my results at anything other than point blank range or beyond reasonable flash range have been characterised by consistently good exposure. If they could do it then, why can they not do it now? *sigh*

[stevebrot]

The big frustration for me is that the uncrippled mount only just failed to survive into the DSLR era; even the MZ-S's mount is crippled IIRC

The original crippled KAF mount was initially used on just a few low-end MZ/ZX bodies (MZ-30/ZX-30, MZ-50/ZX-50, MZ-60/ZX-60) and eventually on the *ist film version. The rest of the film bodies had the standard KAF, KAF2, and KA2 mounts right up until about 2005.*

Regrettably, the form factor of the *ist film camera along with a KAF2 version crippled mount were migrated to the *istD in 2003 and the rest is history


Steve

* When I first joined Pentax Forums in 2007, it was still possible to buy a MZ-S as residual stock from major dealers.

[wombat2go]

More with the AF080C on the ist ds:

1) The flash exposure compensation on the camera adjusts the flash level, although that adjustment requires hunting through the menu.

2) The first photo below shows approximately the radiation pattern of the AF080C when used as a conventional flash.
This wide angle pattern is an indication of why the GN is so low.

3) In the second photo, with the SMC Pentax 1:2.8 24mm, I angled the AF080C on the flash bracket so it was pointing vertically illuminating the ceiling.
The table lamp is a deteriorated 15 Watt CFL. The ist ds was set up to 400 iso, and the flash "A.Check" green light flashed , indicating that the exposure was OK.