Hi Andrew,
Are you referring to this lens,SMC Pentax 400-600mm Reflex. I'm not into zoom lenses but that does not stop me from trying it when you next come to SA. Give me a call.

Greg

As an update on this old post.

I found my Pentax K 500mm f4.5 today paid the equivalent of UKP 350.00. Comes with the original box, leather case and factory certificate and is in perfect condition.

I'm a happy man.

In theory that means that I've bought the last of the MF lenses I set out to get, that does not mean I won't be tempted

Greg

I ran a quick test, because I did not believe that only the flash to target distance was important and I hate to have to admit that I can move the camera closer and further from the target without changing any settings on the camera and all the exposure levels were very similar.

Even when zooming in and out the exposure remained remarkably consistent.

This will make life much easier.

Thanks for all the feed back
Greg

Sorry it's still not clear in my mind.

Are you saying that if I set my camera to f4 and ISO 200 at, point A, and then 30M away, at point B, I set up the flash in auto mode, also set to f4, ISO 200 and aimed at a target, point C, which is 3M from the flash but 30M from the camera that I do not have to compensate for the light falloff between the camera and the target?

The flash would have based it's exposure on the reflection from the 3M distance to the target.

Surely there must be drop off in light between the target and the camera which will cause under exposure.

Please be patient
Greg

I know this is a stupid question but if I don't ask I'll never know for sure.

The flash will be set to auto, so it will expose for the distance it's from the subject using the ISO and f stop I've selected, but my camera will be say 30M from the flash and subject, must I take into account the fact that the light falls off at the square of the distance from the subject to the camera.

In other words must I make the flash overexpose to compensate for the distance?

Greg

I live in Pretoria.

This issue is becoming more and more complex I do have a very high voltage portable electric fence which I made and we sometimes string it around the camp site, particularly when camping in Botswana, the hyenas are a pain.

I can see the set-up time becoming longer and longer.

Greg

Well I've run a test with my AF- 540FGZ mounted on the Yongnuo receiver and the transmitter on the camera, the flash fires at my test distance of 60M, not line of sight. With the 540 set to Slave 2 and PH2 and auto mode, it has not yet gone into standby, I'm Still waiting to see what happens.

Thanks for all the help, you've made me rethink the whole process and for the first few times I'll try this set-up, hold thumbs that the monkeys or baboons don't take off with my flash

Greg

I want to set-up the flash very near a waterhole and then wait in the car, which can be 30-40m away, for the game/birds to come and drink. I would prefer a LCD with LARGE letters as my eyesight is marginal and the action takes place at dawn. A torch and eyeglasses would work, I was looking for a more convenient set-up.

Disabling the standby is an essential requirement, and I don't need any fancy compatibility modes.

Thanks
Greg

I know, I was trying to avoid that $$$$$

I have a Yongnuo RF-602TX wireless trigger which I use as a very long range remote release, I have not yet tried it's flash controller functions but may well have to use it at those distances.

No cheaper alternatives?

Greg

Hi,
I'm looking for a flash which has an illuminated rear screen showing the set-up configuration.

It will be mounted on a remote tripod about 25 or more meters from the camera and the basic requirements as I see them are
Auto mode
Abt 30GN
Ability to disable the standby mode.

I'll use an optical trigger tripped by my AF540FGZ to fire the flash, the Pentax AF360FGZ's standby mode can not be disabled

Any suggestions please.

Greg