ME Super and AF Flash


Snapper_UK

Link Posted 04/01/2013 - 20:22
I have read the instruction manuals for both the camera and the flash but am still struggling and wonder if someone can advise me?


I am not seeking to use the flash in manual mode but instead probably using green but perhaps red.


I think I am being told that if I use green I should set my aperture to f8 as I will be using a 400 iso film. I am presuming that this will work for all distances from 1 m to 4 m ?


What I can't understand is if I want to use a different aperture . The manual talks about being able to use two F stops in the green or red mode but I cannot understand how this works and which F stops they mean as the scale on the back of the flash has seven to choose from.


The scale on the back of the flash also seems to be at odds with the manual in that the correct setting for a shot using green mode, 2 m from the subject would involve an aperture of 16 and not 8 as the manual says.


Can anybody throw any light on this for me?


John.

gartmore

Link Posted 05/01/2013 - 10:27
I don't follow paragraph 4 and it would help to know which flash you are referring to.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

stevejcoe

Link Posted 05/01/2013 - 12:30
Ok not sure what flash you are using, but this is how automatic flash works on a AF200T (also includes TTL for 'A' series and later)and presumably a AF200S.

There are two automatic settings, What this means is that the flash when fully charged has sufficient power to provide full exposure using the recommended set of parameters. The amount of light that the flash provides will be controlled by the sensor on the front and because there will always be some ambient light, the flash will rarely fully discharge. These flashes still work reasonably well in auto, or manual modes on modern Pentax DSLRs.

Green - for use with wide to normal lenses from 0.6m to 3.5m. Suggested aperture varies according to film speed at ASA 32 it is F2.8 at ASA 800 it is F16.

N.B range is extended to 5m if a telephoto lens is used

Red - for use from 1.5m to 7m. again suggested aperture varies according to film speed. From F1.4 at ASA32 to F8 at ASA800 with a wide to standard lens.

N.B again range increases if a telephoto lens is used, this time to 10m.

You will see from the above that there is an overlap of ranges. Therefore if you are using a standard lens and the subject is between 1.5m to 3.5m away , you will have a choice of apertures. For example using an ASA 200 film you can choose Green F8 or Red F4.

Also note that Pentax made adapters for these flashes designed for wide angle and telephoto lenses. Consult the manual for how they affect exposure.

Regards - Steve

Snapper_UK

Link Posted 05/01/2013 - 23:27
Hi

Sorry it is the AF160

I understand that green mode is from 1-4 metres and red a little further. I understand that for green mode the suggested f stop is f8. What I dont follow is whether I can use different F stops in green mode and if so how this works and effects the flash. Similarly I wonder how this works with red mode too?

johnriley

Link Posted 06/01/2013 - 01:07
The auto function of a flashgun relies on knowing that a particular aperture is set. Then the flashgun can measure the light received from the subject and cut off the flash when enough has been received.

If you are outside the specified range or wish to use a different aperture then it's back to manual use and calculating the exposure.
Best regards, John

Snapper_UK

Link Posted 06/01/2013 - 01:15



John that is not what it says in the confusing blurb in the manual. I believe you have a choice of f stops and not just f 8 at 400 asa in green mode. I cant work out how or why though!

John
Last Edited by Snapper_UK on 06/01/2013 - 01:16

johnriley

Link Posted 06/01/2013 - 01:20
That's actually what it does say John.

The simple thing to do is use either mode and the appropriate aperture that goes with it. This set of instructions doesn't specify what those apertures might be, but let's say f/4 or f/8 as an example.

If you PM me we can talk it through by telephone.
Best regards, John
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