Yes, I probably wasn't very clear. As the aperture changes the flash will compensate. I should probably rephrase that comment and move it to the intro.
I shot a series in Av mode, running the aperture from f/2.8 through f/11. In Av mode, with the flash on, the camera seems to like 1/125 sec shutter speed. I could clearly see the flash change it's power output from shot to shot. In this series all of the backgrounds are about the same, but you can see the depth of field change. In Tv mode I ran the series from 1/4 sec to 1/180. At 1/4 sec the camera chose f/3.5. It chose f/2.8 at all other shutter speeds. The results were similar to the manual mode series. In the end I used manual so I could control as many variables as possible. GS <http://georgesphotos.net> On Sun, Jun 1, 2008 at 11:45 AM, Bob W <[EMAIL PROTECTED]> wrote: > That's quite instructive. In the 3rd picture, though, you write "Flash > adjusts output to keep the foreground subject correctly light". The > flash doesn't need to adjust the output - for the same distance and > aperture the flash output should remain constant, and TTL isn't > needed. > > Bob > >> -----Original Message----- >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On >> Behalf Of George Sinos >> Sent: 01 June 2008 17:14 >> To: Pentax-Discuss Mail List >> Subject: GESO - Balancing flash with available light >> >> Balancing flash with available light. >> >> This is a gallery of a few shots put together for a class drill. > The >> idea is to light the foreground subject with the flash and the >> background with available light. The lightness/darkness of the >> background is controlled by changing the shutter speed. The aperture >> is held constant for all photos. The P-TTL flash keeps the subject > lit >> at the desired level. >> >> For the Pentax folks here's a little additional info. >> >> The Flash is a 540 set in the wireless mode. It's set to +1/2 stop >> flash exposure compensation. It's zoomed in as far as possible to >> narrow help keep light from spilling onto the background. There are >> only seven images in the gallery, but I did a lot of experimenting > and >> fired the shutter just short of 100 times. The flash is very close > to >> the subject so it probably didn't need to use much energy. Even > when >> I was experimenting with very small apertures requiring noticeably >> more powerful flashes the flash recycled almost immediately. The AA >> alkaline batteries seemed to work OK for this application. >> >> The lens is the DA* 50-135mm f/2.8. The focus point is the black >> queen in the back row. >> >> The camera is the K20d, flash set to wireless control mode. Manual >> mode for this series. Though I had set the white balance to > daylight, >> it didn't make any difference. I had custom setting at "WB auto > when >> flash attached." I've since set it to "unchanged" so it will use > the >> WB as set on the camera. No matter, I was shooting raw files. >> >> Here's the link >> >> <http://Georges.smugmug.com/gallery/5066768_nv8WE/1/304882093_iUGLx> >> >> Oh, the opening image documenting the setup was shot with a Canon > G9. >> >> This was time well spent, if only to learn about the custom settings >> on the camera and flash that interact. I've only had the K20 and > 540 >> for a short time. >> >> GS >> <http://www.georgesphotos.net> >> >> -- >> PDML Pentax-Discuss Mail List >> PDML@pdml.net >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly >> above and follow the directions. >> >> > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
