Standalone use of METZ SCA 346/2 AF

frankie0815 · Nov 9, 2023

hello. i am new to this community.
i am 57 years old, from germany. i am a hobby photograf mostly using old analog Nikon stuff like F3, FA, FE2, FG, F90x, F501, but also some older DSLR (i.e. D200).
My newest item in my collection is a Nikon F3AF with AF lens and AF TC-16, which i like very much.

My question here: i recently saw the METZ SCA/2 AF adapter. can this AF-light be used as stand-alone without any METZ flashlight?
i want to use it as AF light in a case, where remaning light is too low for the older cameras AF system.
The old AF systems where very bad, not to compair with todays cameras. Only contrast AF with horizontal sensors. need much light and high horizontal contrast. else af is not able to focus.

assuming, the metz SCA 346/2 can do this, it would be nice having some red light stripes on the objects i want to focus on.

any suggestions about that?

thank you in advance, FRANK

koraks · Nov 9, 2023

Welcome to Photrio, @frankie0815 ! I don't know the answer to your question, but no doubt someone else will be able to chime in.

Just to be sure I understand properly: you have a Metz SCA 346/2 AF adapter that sits on the hot shoe of your Nikon autofocus camera and you wonder if it'll emit an AF-assist illumination beam even if no Metz flash unit is connected to it, right? Isn't this something that's easy enough to just test? If you've tried it, what were your findings?

frankie0815 · Nov 9, 2023

I dont have it, but i would consider buying it, if it works somehow.
not for F3 but F-501.

removedacct3 · Nov 9, 2023

There is a switch on the back of the adapter that lets you choose between automatic flash, manual flash and focus assist only. And according to this document it should work on a F-501.

http://www.film-and-darkroom-user.org.uk/forum/attachment.php?attachmentid=2201&d=1416749739

The proof of the pudding is in the eating, but without the eating I would assume it does not require a flash for AF assist only. My 374/2 AF module for Pentax (I know different system) does exactly what you want.

frankie0815 · Nov 9, 2023

Seems that it will work. I will buy one, try and report here. Thanks a lot everyone.

ic-racer · Nov 9, 2023

Using focus assist only seems like a neat idea. My Metz 45 flash has this feature, but the red lamp is not that bright. In fact, if it is that dim that one needs the focus assist, wouldn't one also need to use the flash too?

frankie0815 · Nov 13, 2023

I just found i am not the only one, who wanted to use the SCA autofocus assistent light standalone.
some stated, the SCA autofocus light wont go without a flashlight telling it is ready to flash.
but there is a workaround using a solder bridge which is decribed here (german website): af hilfslicht

but one question remains: how does the camera activate the af-light, which contacts of the hotshoe are involved, and how?
is there any schematics of the nikon flash shoe? i dont find anything.

neilt3 · Nov 13, 2023

frankie0815 said:
but one question remains: how does the camera activate the af-light, which contacts of the hotshoe are involved, and how?
is there any schematics of the nikon flash shoe? i dont find anything.

I would ask , how is the lamp powered ?
These things are designed to be fitted to a flash , and the flash has the batteries in it .
As far as I know non of the control modules have batteries.
So if the flash is the power source , it would still be needed .
The way I read the O.P was to use it as a stand alone unit , that is without the flash attached , not just switched off .
I might have misunderstood the O.P's intentions though .

EDIT ; just to add , later AF units do use batteries in the module, it's just this one I'm not sure on .
It might be if a complete flash unit isn't placed on the camera , then nothing works anyway .

koraks · Nov 13, 2023

frankie0815 said:
is there any schematics of the nikon flash shoe? i dont find anything.

It may help to Google for 'pinout'. I find e.g. this:

Nikon TTL Hot-shoe interface pinout signals @ PinoutGuide.com

Nikon Hot Shoe Pinouts | DSLRBodies | Thom Hogan

Nikon hot shoe pin outs

www.dslrbodies.com

There's also this discussion that goes a little deeper, in particular highlighting how the pinout essentially changes once a modern Nikon camera detects an iTTL-capable flash unit, enabling bidirectional communication: https://www.photo.net/forums/topic/350110-anyone-know-the-contact-configuration-of-nikon-flash/
However, keep in mind that what Nikon decides is one thing, but how Metz approaches the issue of communications between their AF module and a flash unit is quite another.

If I'm to make an educated guess, I'd expect the Metz system to present an iTTL-capable device to the Nikon camera, which then communicates with it, including signaling actions such as 'focus'. The Metz unit then receives this and takes action, which can include enabling the AF assist beam.

I think what you'd want is the description of the Metz pinout and communication protocol if you want to verify if shorting two contacts will indeed trick the Metz AF unit in believing a Metz flash is present.

neilt3 said:
As far as I know non of the control modules have batteries.

Good point. If the AF assist module doesn't have a battery, it's not going to work autonomously.

frankie0815 · Nov 13, 2023

in this case, the METZ 346/1 AF has its own batteries.
my aim is: half way push camera shutter release and AF-light lights up.
no iTTL or something else, it is only old analog, pre-DSLR.

koraks · Nov 13, 2023

frankie0815 said:
no iTTL or something else, it is only old analog, pre-DSLR.

I'm not so sure about the 'no iTTL' part. Consider this:
* The Metz 346 is brand-specific. This suggests that it interfaces specifically with Nikon, Canon etc. depending on which variant you purchase.
* Since it's brand-specific, it's likely (guaranteed) to interface with iTTL with a Nikon camera.
* While DSLR's might have additional features, iTTL was already around in the analog era and it remains compatible. Hence, the pinout for iTTL dSLR's will be the same for analog Nikons.
* Since there's apparently no contact dedicated for 'focus engage', it's likely that this is part of the iTTL communication between the camera and the AF assist module.

The whole iTTL business still doesn't say anything about how the Metz 346 communicates with a Metz flash unit, and how/to what extent it needs to 'detect' an installed flash unit. That's a separate issue.

frankie0815 · Nov 13, 2023

Yes, the 346 /1 and /2 AF is only for Nikon, it has a Nikon flash shoe suitable for the whole range of old non-AF models i.e. EM FG FA FE-2 FM-2 and the early analog AF-models from F-301 to F-801, F4.

frankie0815 · Nov 13, 2023

koraks said:
It may help to Google for 'pinout'. I find e.g. this:

Nikon TTL Hot-shoe interface pinout signals @ PinoutGuide.com

Nikon Hot Shoe Pinouts | DSLRBodies | Thom Hogan

Nikon hot shoe pin outs

www.dslrbodies.com

There's also this discussion that goes a little deeper, in particular highlighting how the pinout essentially changes once a modern Nikon camera detects an iTTL-capable flash unit, enabling bidirectional communication: https://www.photo.net/forums/topic/350110-anyone-know-the-contact-configuration-of-nikon-flash/
However, keep in mind that what Nikon decides is one thing, but how Metz approaches the issue of communications between their AF module and a flash unit is quite another.

the links helped a lot, thank you!

koraks · Nov 13, 2023

Great, that's good to hear!

If you get this to work, please be sure to post back.

frankie0815 · Dec 20, 2023

Sorry for the long time without an answer.
Short point: it does not work. I dont get a autofocus light.
I connected the contacts according to this picture:
I get a flash ready sign in the viewfinder now.

But the red light is not working.

I tried this with my F501 which is supported by the Metz SCA 346/2 AF. But without a flash connected i dont get the AF light.

koraks · Dec 20, 2023

That's a pity. You do get the AF beam if you put a Metz flash unit on top? Or haven't you been able to verify this?

frankie0815 · Dec 20, 2023

I dont have a Metz SCA flash but i will buy one.

Chan Tran · Dec 20, 2023

I am quite sure it won't work on the F3AF.

frankie0815 · Dec 20, 2023

I would be satisfied if the F-501 will work in this configuration.

neilt3 · Dec 20, 2023

frankie0815 said:
I dont have a Metz SCA flash but i will buy one.

It's quite possible that without a flash attached to complete a circuit, it won't do anything anyway.

Regards the camera setting off the AF illuminator on the F3AF , did Nikon sell a flash with an AF illuminator on when that camera came out?
If not , it might be the camera the issue .
If the flash sold with the camera didn't have an AF illuminator, then the circuit needed to tell the flash to light it up would be missing.
To rule that out , fit a modern Nikon flash to the camera and see what happens.

Also , what AF unit is in the camera ?
Some early AF units were similar to p&S cameras where it had some sort of range finder built into the lens .
These don't always work the same way as AF SLRs, so a light might not help.

frankie0815 · Dec 20, 2023

Ok. With the F-501 it is working standalone without flash.
At first try i did not set the AF switch.
Now it works.
If i push the shutter half way i get a nice red barcode on the wall which the camera can focus on.
I did not want to open the SCA so i attached the cable to the SCA contacts just pinch it into the spring contacts.

frankie0815 · Dec 20, 2023

Looks like this:

koraks · Dec 20, 2023

Cool!

neilt3 · Dec 20, 2023

frankie0815 said:
Ok. With the F-501 it is working standalone without flash.
At first try i did not set the AF switch.
Now it works.
If i push the shutter half way i get a nice red barcode on the wall which the camera can focus on.
I did not want to open the SCA so i attached the cable to the SCA contacts just pinch it into the spring contacts.

I see . So your just joining the two contacts so it thinks the flash is attached.
Does it help the camera lock focus well now ?

It does sound like the F3AF doesn't support AF illuminators , but unless someone here also has one that can try a flash that also has the AF illuminator on , we won't know .
Can you not get to a camera shop to try a new flash to see what happens?
Not all modern flashes expose correctly with film cameras , but the AF lamp would work regardless , if the camera supports that function.

frankie0815 · Dec 20, 2023

Tomorrow i will try my F3AF and AS-17 with this AF-light.
F-501 can lock focus with this one - even in light conditions when focussing normally is not possible.

Never the less i will modify the SCA for use with the F-501, using a SCA300A cable, remove the cable and add a small switch instead.

Standalone use of METZ SCA 346/2 AF

frankie0815

koraks

Moderator

frankie0815

removedacct3

frankie0815

ic-racer

frankie0815

neilt3

koraks

Moderator

Nikon Hot Shoe Pinouts | DSLRBodies | Thom Hogan

frankie0815

koraks

Moderator

frankie0815

frankie0815

Nikon Hot Shoe Pinouts | DSLRBodies | Thom Hogan

koraks

Moderator

frankie0815

koraks

Moderator

frankie0815

Chan Tran

frankie0815

neilt3

frankie0815

Attachments

frankie0815

koraks

Moderator

neilt3

frankie0815

Standalone use of METZ SCA 346/2 AF

Moderator

Moderator

Moderator

Moderator

Moderator

Attachments

Moderator

Privacy & Transparency

Privacy & Transparency