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View Full Version : Manual Lenses and the Pop-up flash



DonSchap
07-06-2007, 07:42 PM
Well, using MANUAL lenses really is a manual process.

Manual all the way, in fact, from the flash point of view.

I have found, through basic trial and error testing, that the “pop-up” flash will work quite well with the modern and sophisticated TAMRON AF18-250mm f/3.5-6.3 XR Di-II LD Aspherical (IF) lens. The advance measurement system calculates the electronic input from the lens circuitry, adjusts for just the right amount of maximum flash with the metering and “snap”, you got a terrific looking and well lit image.

Unfortunately, the pop-up flash works horrendously with an Manual aperture and focus lens. The reason being is that the camera’s decision-making is based on it knowing the aperture of the lens on the camera. The Adaptall 2 and other manual adapter lenses do not provide this electronic information because there are no electrical connections or methods to provide it to the camera. You can’t even manually set it. AFter reviewing the EXIF data on the rear LCD of the camera, the SONY camera assumes an unbelievable f/1.0 aperture, attenuating the flash to a mere ¼ of normal “full” burst.

Only an external flash (such as the SONY HVL-F56AM or Minolta 5600 (D) HS will allow you to set a “Manual Flash” setting on it. You can set a “ratio” on the flash, also, but I use "1/1" (full pop) just to keep it simple. Set your manual zoom to match the focal length of the lens, also. You get a full burst of flash and you can vary your shutter from 1/60 to 1/250 or change your aperture, up or down, accordingly to get the right exposure.

If you forget and keep the flash on TTL mode, be prepared for some pretty dark images. A real f/1.0 lens is hard to find. I won't even address the costs of such incredible glass.

It’s kind of weird to be out to 250mm @ f/6.3 with the AF lens and get a brighter flash image than a 200mm @ f/3.5 MF lens with the same camera and subject, but the pop-up flash has only one idea of what to do ... so it minimizes its output to reflect the use of a f/1.0 lens. This could explain some of the problems are being seen with the SONY DT18-70 kit lens, when using the pop-up flash. Somehow, the TTL information is not making it back to the flash calculator.

These are simply things to consider when using MF lenses with TTL metering camera bodies.

Using ambient light, then you begin to arrive on a playing field where the manual lens can compete and show its stuff. The 200mm f/3.5 blows away the 200mm f/6.3 hands down. You get 1 & 2/3-f/stop more light into the sensor ... and that can save the day on an indoor, no flash shot. The MF 135mm is quite a bit brighter than the equal focal length setting on 18-250mm ... which is still at f/6.3. Nearly 3 f/stops brighter.

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AF18-250 @ 135mm @ f/6.3 (no bokeh) . . . . . . . MF 135mm @ f/2.5 (w/ that 2.5 bokeh)


Good luck with your craft. :)