[shortphaselabs]

I use a few old lenses and am very familiar with green button stop down metering but as I look at the amazing differences in capability and cost of, say, Godox 850II flashes compared to OEM, I wonder what other options we have. Cost and capability are what drove me to Pentax in the first place but this is not reflected in flashes.

So I ask; why does the green button not do the same thing for flash? You could set your output to what you want, just like aperture on a manual lens, and hit the button. It fires the flash, stops down the lens, and makes an adjustment. If you do not have a manual lens it would be able to work in Av, Sv, Tv modes as well.

Am I missing something? This would allow us to meter every flash TTL.

[stevebrot]

Am I missing something? This would allow us to meter every flash TTL.

In P-TTL, it is the body that controls the flash attenuation. The flash must support the means to do so. In the scheme you propose, the only automated adjustment available to the system would be a change of aperture and/or ISO. Note too that there is also the matter of the body knowing that flash metering is desired.*


Steve

* Flash metering is somewhat different than ambient light metering.

[shortphaselabs]

It could also adjust the shutter speed as with manual lenses.

As for deciding whether flash metering is desired, it would be an easy menu option. When you hit the green button do you want lens, flash, or both? We know the camera can sense when a flash is attached because it will limit the shutter speed to 1/180 or slower even when a simple manual flash is attached.

[Nicolas06]

It could also adjust the shutter speed as with manual lenses.

As for deciding whether flash metering is desired, it would be an easy menu option. When you hit the green button do you want lens, flash, or both? We know the camera can sense when a flash is attached because it will limit the shutter speed to 1/180 or slower even when a simple manual flash is attached.

This is possible, but basically, this would require to release a flash each time you press the green button.

Anyway, Pentax want you to buy Pentax flash and all are automatic theses days. And a compatible TTL flash from Metz go as low as 80€. You likely can find one cheaper used.

If you are in studio, you'll want anyway to control the exact lighting of each flash so you'll control their intensity manually to craft the light. Pro will use a high quality radio controlled trigger system and a set of high quality flash and that be nowhere innexpensive.

---

Last edited by Nicolas06; 07-23-2016 at 11:39 PM.

[shortphaselabs]

They also want you to buy new lenses but offering the green button sets them apart. Godox and others offer manual flashes which can be controlled remotely. See the Godox 850II. All I want is a chance to meter from it without as much trial and error. The vision for the shot would not always match the metered result but you would be close in an instant. The biggest benefit to this is for photojournalists or wedding photographers who really gain from p-ttl. A simple firmware update would allow an amazing jump in possibilities for every Pentax dslr. This really isn't different than p-ttl with the exception that we tell it when to preflash vs preflashing automatically. Same capability, no new or expensive flash unit. Pentax has a sadly small pool of flashes to draw from if you want p-ttl. The incredible things coming from China have Canikon covered a hundred times over but Pentax is nowhere to be found.

[stevebrot]

It could also adjust the shutter speed as with manual lenses.

That is the hitch with flash photography. Shutter speed is not a factor for the flash component of exposure. The variables are distance, aperture, ISO, and flash output.

As for the camera "sensing" when a flash is attached, that is true when a Pentax-dedicated flash is present, but not true otherwise. Neither the hot shoe nor the PC connection will fire if shutter speed is set above 180s. This is true regardless of whether a flash (dedicated or not) is mounted. The sole exception is when a dedicated flash in HSS mode is detected.

Based upon the description of your needs (specifically the Godox 850II*), I would suggest a hand-held flash meter.


Steve

* Basically a speedlight that offers brand-agnostic HSS when fired from a compatible Godox wireless trigger.

[Nicolas06]

They also want you to buy new lenses but offering the green button sets them apart.

The difference is many people have old lenses and many would choose Pentax over the competition because they have old K-mount lenses. If you remove that, you remove the interrest to stay in Pentax. People have far less flash than lenses, the money invested is much smaller and it would not change the decision of most old Pentaxian to stay or leave Pentax.