[Bui]

As a disclaimer, I have never used flash, so no knowledge or flash experience, and decide it's now a good time to discover this dimension. Before splashing some cashes to buy a flash, I would like to ask you whether a legacy flash can be used with a modern Pentax camera, similar to the way a legacy lens being used? For example I have a AF220T TTL and a AF400T, and also 2 other legacy flashes that I don't remember the model. Can I try them first to learn some basic things about using flash, and what would I miss using them instead of purchasing an average modern one?

Thank you.

[ismaelg]

Hello,

NO! Let me explain: Beware of the voltages. Modern cameras operate at very low voltages in the hotshoe. Old flashes are very high voltage and can fry the electronics of a modern camera. Rule of thumb: Assume it is not safe until proven otherwise. Somewhere, there was a list of flashes with voltages and what was safe on modern cameras. Can't find it but I'm sure somebody here has it.

Thanks,

[garywakeling]

try here for lots of answers
Comprehensive Pentax P-TTL Flash Guide Updated - Articles and Tips | PentaxForums.com

[blumoon722]

This site lists lots of flashes and their voltage:
Photo Strobe Trigger Voltages

[pschlute]

As a disclaimer, I have never used flash, so no knowledge or flash experience, and decide it's now a good time to discover this dimension. Before splashing some cashes to buy a flash, I would like to ask you whether a legacy flash can be used with a modern Pentax camera, similar to the way a legacy lens being used? For example I have a AF220T TTL and a AF400T, and also 2 other legacy flashes that I don't remember the model. Can I try them first to learn some basic things about using flash, and what would I miss using them instead of purchasing an average modern one?



Thank you.

Your AF220T and AF400T are TTL (through the lens) flashes.

Modern Pentax digital cameras require a P-TTL (pre-flash through the lens) capable flash unit, so you wont get any automated exposure with your old models. The AF400T may work in manual mode. The AF220T does not appear to have manual settings so that wont work at all.

You really would do better to go for a modern flash unit that can communicate with your camera.

[stevebrot]

The rule of thumb goes like this:

• All Pentax-brand flashes are voltage-safe with all Pentax K-mount cameras (Edit: with possible exception of the early 1970s AutoRobo model)
• All Pentax-brand flashes are broadly compatible (dedication, flash automation, etc.) with all Pentax K-mount cameras to the extent of their shared features. In some cases, that may mean manual flash only with little or no dedication.

That last is the sticky point, but may provide some happy surprises. I regularly use an AF280T with my K-3. No, it does not support P-TTL, but its behavior on the K-3 when used in either of its "Auto" (auto thyristor) modes includes working with the camera to set appropriate shutter speed and aperture. My review of the AF280T provides details (LINK).

The flip side is that several legacy Pentax flash have features that are closely tailored to camera models being sold at the time the flash was made. The most difficult case being some fairly sophisticated models that support TTL (digital protocol only) and manual modes only. Probably the most notorious being the AF500FTZ and AF220T which are broadly incompatible, feature-wise, with both manual focus film cameras and dSLRs (except *ist D/DS/DS2).

Can I try them first to learn some basic things about using flash, and what would I miss using them instead of purchasing an average modern one?

There is no harm in using the AF220T or AF400T on your Pentax dSLRs. The AF400T in "auto" modes should behave much the same as my AF280T (see above), meaning that it should be quite usable.* The AF220T is TTL (digital protocol) dedicated and will operate as manual flash only on your dSLRs. The manual for the AF400T is available at the Pentax Manuals site (LINK) and that for the AF220T is probably at the Butkus site (LINK). What you miss relative to modern flash is convenience (huge), P-TTL exposure automation, and ability to act as optical master/controller/slave for off-camera operation.


Steve

* Note that you will require the 4P Sync Cord B or similar for dedicated hot shoe use. I would experiment with how it behaves in the various exposure modes when using "auto" and suggest Tv or M modes. Using the PC sync only, "Auto" flash exposure will still work, but will require manually setting the flash.

[Apet-Sure]

I have two vintage Vivitar 283 flashes. One I bought in the 70's and the other about three years ago. The older one has a trigger voltage of over 300 volts! The newer-to-me unit has a trigger voltage of 8 volts. I have put the second one directly onto the hot shoe with no reservations. The first one would probably 'precipitate a demise' as my dad used to say. I did a fair amount of reading from various sources regarding 'safe' trigger voltages for modern cameras. There was no hard and fast consensus. Some say nothing over 24V, some say 10V or less.


As a side note, I've had training in industrial electrical safety. When measuring voltages that may potentially be high (say 50V and above), only use brand-name, UL and/or CSA listed meters (in the USA) or equivalently tested meters in other locations. I've seen videos of cheap meters that claim to be designed to UL standards, but blow up when measuring voltages they should be able to handle. If a meter doesn't have the UL or CSA logo (or equivalent), it hasn't actually been tested and approved by those agencies.

[C_Jones]

I would recommend the Yongnuo 585EX for Pentax if you are searching for a new flash. It has Pentax TTL (P-TTL) capability when used with Pentax cameras. I have one along with my 3 Pentax flashes. It is an excellent flash. Below is a shortcut to the product. There is also a product called a safe-sync adapter for use with old flashes, but I am not sure if it would be safely applicable to your situation. Using a new dedicated flash with TTL like the one mentioned below may be a good step.

Yongnuo YN585EX Speedlite for Pentax Cameras YN585EX/PENTAX B&H

[Joe Dusel]

I recommend buying a Pentax compatible Godox flash. Godox has a complete system that works with Pentax cameras, and if you decide it is something you like it will give you a lot of flexibility, especially if you get into off-camera flash.

[clackers]

I wouldn't bother, Bui, go for shiny, new speedlights. Even the cheap ones these days are quite good.

I have an expensive Godox strobe and trigger but to be honest get more use out of the budget Yongnuo system - radio controller with four flashes (built in radios) costing little.

[Dale H. Cook]

I have two vintage Vivitar 283 flashes. One I bought in the 70's and the other about three years ago. The older one has a trigger voltage of over 300 volts!

Despite that voltage and the lack of most modern features the '70s-vintage Vivitar 283 is still in use. It can be modified by experienced technicians for 5 volts on the hotshoe and for manually adjusted flash duration. I have two 283s that I have modified in that manner and that I use as off-camera flashes with wireless triggers. Because of my long experience (nearly 60 years) in electronic construction, repairs, and modifications, and my well-equipped electronics shop (which I also use for work), I was able to do that myself. If I had to charge someone my bench labor rate for those modifications they would be better off buying a used flash with a lower hotshoe voltage.

[Apet-Sure]

If I knew how to do the voltage mod I might try it myself. I took electronics technology in college (long time ago, but many principles still apply) and have built simple amps, guitar pedals, and other gizmos over the years. Would you care to PM me the instructions Dale?

I have most of the accessories for the 283, including the module for manually adjusting output power (thus the flash duration I assume). The 283 is dated but is quite capable and has plenty of power for my purposes. At its native 50mm FoV coverage it has a guide number of 120 at ISO 100. Compare that to camera pop-up flashes which seem like they are usually in the neighborhood of 13 or so.


One of my pet peeves with modern flash advertisements is that they often give the guide number spec at the unit's max. telephoto FoV coverage. Well, yeah, if you concentrate the light cone the number will go up, duh. IMO it's misleading when you are trying to get a feel for the units actual power output. What if the next brand focuses to 120mm instead of 100mm? I think the guide number spec should be at some standardized FoV, say 50mm (like in the old days) or 33-35mm for APS-C use. If every manufacturer specs a guide number for their particular max. telephoto FoV, the numbers become somewhat meaningless, or at least harder to interpret. Heck, with my 283's 135mm lens attachment, it's guide number becomes 174 at ISO 100. But its 'real' rating is still 120.

Rant over.

[Dale H. Cook]

Would you care to PM me the instructions Dale?

I started by buying a copy of the service manual for the 283 so I could get it apart without damage and put it back together correctly, as well as having the schematics and board layouts that I needed. I also strongly suggest documenting every step of the process with photographs. I have another 283 in the shop awaiting conversion, and I now have a mount above the bench for my K-70 so that, with WiFi Commander, I will be able to easily and thoroughly document the modification process. When that documentation is done I will post it on my site and post a link here. With that level of documentation you will not need a copy of the service manual. I do not expect to get that documentation online until perhaps late fall, as late spring through early fall is my busy season at work. After spending hours each week beating on electronics for a living I am little inclined to do so for fun, so projects like this are reserved for the cooler months.

I have most of the accessories for the 283, including the module for manually adjusting output power

I presume that you mean the VP-1 Varipower module, which provides six settings. That module is rather crude compared with my mod which puts a miniature 12-position rotary switch inside the flash body in place of the 5-pin domino DIN socket for the sensor module, providing flash durations from 1000 microseconds to 20 microseconds in 1/2 f-stop steps. Because I am using my 283s off-camera with wireless triggers and I am not trying to freeze fast motion, so 20 microseconds is fast enough for me.

I built a calibration jig to select resistor values for the desired flash durations for each flash. I will give resistor values (and parts sources) when I post the directions. My 283s have calibrated durations as I sometimes use multiple flashes off-camera and wanted the indicated durations to be fairly precise. When I post the modifications the resistor values that I will give will be commonly obtainable values precise enough for most people's needs.