[JimJohnson]

Success! I now have a 25 foot TTL cord using the Cat5 method. I think for off-camera HSS this is going to be the best solution, at least the way I intend to use it. With careful framing, I should be able to get the flash within 1 meter of my subject, but still be 20 feet away. This should strong enough to get the skies fairly dark, even at noon.

A couple things that I learned in making mine:

• It's hard to strip coiled cable, and man are those TTL cords well insulated.
• You don't have to pre-strip the ends of the inner wires, in fact, don't. When you crimp the RJ-45 plug there are little copper blades that push themselves down into the wire.
• I had 5 insulated wires and a bunch of loose copper threads in my cable that had to be twisted into a wire, I think that is probably the center pin. Some other cables I've seen have 6 insulated wires.
• In order to keep frayed ends from the twisted wire from sliding into the wrong channel on the plug, position that wire to one side, and all the other wires on the other side of the plug. That should leave a buffer of two unused channels between the twisted wire and the next closest.
• It doesn't matter what order you put the wires in, but you absolutely must do it the same way every time you crimp one, or you're liable to fry your camera and your flash. Mine went copper, empty, empty, white, green, yellow, red, black. Your colors may be different.
• Trim all the inner wires to the same length, and make them short enough so that you can fit a bit of the outer insulation inside the RJ-45 plug when you crimp it.

I'll see if I can get some samples this weekend of shots using up-close off-camera HSS.

Having done computer networking for a couple decades, as the saying goes "you done good".

I'll add one note.... there are three broad categories of RJ-45 plugs - those made for solid wire (don't buy those for this type of work), those made for braided wire, and those made for either type of wire. Either of the last type will work fine, but the dual purpose plugs often cost a little bit more.

Marketing units as always promotes things that may not make any difference. A big factor in cost is how much gold is used in the metal parts of an RJ-45 plug. If you are building cables for high-performance, high reliability networks, you want more gold. Personally, for this type of application, I don't think the thickness of the gold plating is going to matter all that much.

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Last edited by JimJohnson; 07-03-2013 at 12:30 PM. Reason: more info

[mattb123]

Nice, I'm looking forward to seeing how your photos come out. I have considered this too but my job no longer requires cable terminating so I'm rusty and I don't have the nice crimper anymore.

[Alizarine]

You can make the cord he describes, but it won't let you raise the sync speed over 1/180th. Nikon cameras lock the shutter speed to 1/500th when they detect a TTL flashgun, but Pentax cameras don't even check for one, they just disable all sync commands above 1/180th. I actually managed to make one last night, unfortunately I was trying to make a TTL cord, hehe (I think one of my wires isn't all the way in the RJ-45 plug)

So far as anything I have read, all current Pentax bodies will disable the flash trigger at shutter speeds greater than 1/180th second, unless the body can detect a flash currently capable of High Speed Sync (HSS - also known as FP) . HSS flash on a Pentax body requires the use of P-TTL.

For reasons given in earlier posts in this thread, I consider HSS flash to have limited use in flash photography.

Thanks for your answers! Well, if that's so I guess there's no workaround for current bodies to sync faster than 1/180 unless in PTTL with a dedicated Pentax flash and mounted.on the hotshoe. *still pinning hopes on future Pentax bodies*

[Lowell Goudge]

Hm. Are you saying that I need to use a P-TTL compatible flash as master and another P-TTL flash as slave? That hoovers.
Does this mean that I can't use HSS i manual mode?

Please tell me that this is incorrect.

So sorry, you got it correct. High Speed Sync requires the flash to strobe as the focal plane shutter moves across the sensor gate as a slit narrower than the gate itself. The timing of these multiple flashes is as you can imagine, rather critical, and P-TTL provides the timing. Even if you do it with a wired off camera flash rather than wirelessly, you still need P-TTL to control the timing.

There are multiple threads here describing how HSS works so I am not going to repeat all that. Bottom line, no manual HSS - it simply isn't possible.

I don't know your intended use, but given how HSS works, its best use is for fill flash in bright ambient lighting conditions. Contrary to what a lot of people might think, it is really not appropriate for freezing action.

Not quite correct, the *istD can run HSS with the built in flash as the master. I do not think any other body can do this however, but if you really want it, get an *istD

[Alizarine]

the *istD can run HSS with the built in flash as the master. I do not think any other body can do this however, but if you really want it, get an *istD

By this do you mean it can set off HSS-capable flashes wirelessly as slaves but not with itself? I mean... by itself, it's still 1/180 max right?

[Lowell Goudge]

Not quite correct, the *istD can run HSS with the built in flash as the master. I do not think any other body can do this however, but if you really want it, get an *istD

By this do you mean it can set off HSS-capable flashes wirelessly as slaves but not with itself? I mean... by itself, it's still 1/180 max right?

No I mean the built in flash can operate i HSS mode and also as the master, and control an off camera slave flash in high speed sync mode above 1/180 it is the only camera to my knowledge in the pentax line up that can do this.

[Class A]

... it is the only camera to my knowledge in the pentax line up that can do this.

I have a feeling it should be "...the only camera in the Pentax line up that is allowed to do this".

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Last edited by Class A; 07-05-2013 at 06:56 PM.

[Lowell Goudge]

I have a feeling it should be "...the only camera in the Pentax line up that is allowed to do this".l

Consisting it also supports TTL as well as P-TTL and the HSS as discussed, it arguably has the best flash platform of any Pentax camera

[p38arover]

Consisting it also supports TTL as well as P-TTL and the HSS as discussed, it arguably has the best flash platform of any Pentax camera

After using my K-5 and AF540FGZ as a combo for the first time last Sunday at my father's 93rd birthday and being very disappointed with over-exposures thus requiring fiddling with EV adjustment, I now wonder if I should have taken my *istD and my old AF400FTZ TTL flash.

Or I should have had a lot more experience before the birthday.

I tried wireless but didn't know I should have switched the camera to Control.

Equally, I could have taken my Pentax off-camera hotshoe and cable to get P-TTL

So many variables.

[maxfield_photo]

Next time try auto mode on the flash, it does a lot better job of judging it's own exposure than the K5 does. OR, learn to love manual flash, and you'll never find yourself faced with the problem.

[Lowell Goudge]

After using my K-5 and AF540FGZ as a combo for the first time last Sunday at my father's 93rd birthday and being very disappointed with over-exposures thus requiring fiddling with EV adjustment, I now wonder if I should have taken my *istD and my old AF400FTZ TTL flash.

Or I should have had a lot more experience before the birthday.

I tried wireless but didn't know I should have switched the camera to Control.

Equally, I could have taken my Pentax off-camera hotshoe and cable to get P-TTL

So many variables.

It's funny, sorry perhaps strange is a better word, but I keep hearing complaints about P-TTL flash and over exposure but personally I don't run Ito this so I get really confused about what people are doing to bring on this problem.

Having said that, however, when I shoot with flash, I shoot with the camera in manual mode. In this way the flash exposure system only manages flash exposure. I set the shutter and aperture myself. I think in the auto modes, there are some assumptions made, which I do not like or agree with. Specifically it seems that the designers assumed flash in any aut mode is for fill only, and therefore set exposure within the limits of what is automatic (ISO shutter and or aperture ) first to achieve exposure, and then and only then increase flash power. I have seen people in auto ISO mode snap on a flash and have the camera take flash shots at ISO 6400 for example.

Too much automation is a scary thing because you are relying on others thinking, and what the camera settings are. Turn most of this off, shoot at max sync speed (in manual exposure mode) set the aperture to give you the depth you need plus ensure the flahs will contribute to the exposure (make sure the exposure meter is to the left of middle) and let the flash exposure system do the rest.

[p38arover]

Next time try auto mode on the flash, it does a lot better job of judging it's own exposure than the K5 does. OR, learn to love manual flash, and you'll never find yourself faced with the problem.

Will do. As I said, more experience needed. I haven't taken flash using an external flash since the '90s with my SFx and AF400FTZ.

It's funny, sorry perhaps strange is a better word, but I keep hearing complaints about P-TTL flash and over exposure but personally I don't run Ito this so I get really confused about what people are doing to bring on this problem.

Having said that, however, when I shoot with flash, I shoot with the camera in manual mode. In this way the flash exposure system only manages flash exposure. I set the shutter and aperture myself. I think in the auto modes, there are some assumptions made, which I do not like or agree with. Specifically it seems that the designers assumed flash in any aut mode is for fill only, and therefore set exposure within the limits of what is automatic (ISO shutter and or aperture ) first to achieve exposure, and then and only then increase flash power. I have seen people in auto ISO mode snap on a flash and have the camera take flash shots at ISO 6400 for example.

Too much automation is a scary thing because you are relying on others thinking, and what the camera settings are. Turn most of this off, shoot at max sync speed (in manual exposure mode) set the aperture to give you the depth you need plus ensure the flahs will contribute to the exposure (make sure the exposure meter is to the left of middle) and let the flash exposure system do the rest.

I made the mistake of mainly shooting in P. I was using the Sigma 30mm f1.4 and too many pix have no DOF. When I look at the EXIF, I can see why. The aperture is nearly wide open - 2.8 and bigger.

Those pics I shot in Av are far better. I haven't checked all photos yet as I was so disappointed. To make matters worse, I took both my K-7 and K-5 but, before I left home I dropped the K-7 and the above Sigma on the carpeted floor at home. That dislodged the focus screen which I didn't notice until I tried taking pix after the screen dropped out unnoticed when changing lenses. It may have also upset the Sigma focussing but that is yet to be confirmed. Let's just say that subjects in images taken outside in good light are OOF but the background is OK.

[JimJohnson]

it seems that the designers assumed flash in any auto mode is for fill only, and therefore set exposure within the limits of what is automatic (ISO shutter and or aperture ) first to achieve exposure, and then and only then increase flash power.

It used to be the other way around. When you used the flash in an auto mode, the camera set itself to its X-sync shutter speed with an aperture that covered typical flash distances and the flash adjusted itself either using its own sensor (autothyristor) or TTL using the camera's sensor. It was easy and reliable and rarely did I bother with manual flash unless I was doing fill and balancing with ambient light.

The behavior you describe is pretty much how P-TTL works today, and frankly it screws up way too many casual photographers.

[Lowell Goudge]

It used to be the other way around. When you used the flash in an auto mode, the camera set itself to its X-sync shutter speed with an aperture that covered typical flash distances and the flash adjusted itself either using its own sensor (autothyristor) or TTL using the camera's sensor. It was easy and reliable and rarely did I bother with manual flash unless I was doing fill and balancing with ambient light.

The behavior you describe is pretty much how P-TTL works today, and frankly it screws up way too many casual photographers.

It depends on a lot of variables. Now it generally sets shutter speed to 1/FL or to max sync for pre FA lenses that don't give focal length to the body. Then depending on mode, will allow either aperture adjustment, or if in TV mode will force combination if aperture and ISO following the program line you have (if it exists)

It is really weird.