I forgot to add : MUCHO THANKS to the engineers at Pentax for putting the magnification ratio index on their macro lenses. This simple technique would be impossible without them. THUMBS UP!
JC O'Connell hifis...@gate.net -----Original Message----- From: pdml-boun...@pdml.net [mailto:pdml-boun...@pdml.net] On Behalf Of JC OConnell Sent: Tuesday, December 23, 2008 12:02 AM To: 'Pentax-Discuss Mail List' Subject: Thanks for the gray card suggestions.. MACRO W FLASH tips RE: homemade gray card, I made a target out of brown cardboard that worked well enough, thanks for all the suggestions. In case theres any of you looking for alternative techniques and dont happen to do things my way, heres how I do flash macro. I use the camera on manual flash full power, iso200, max sync speed (1/180). This is with the *istds. What I do everytime I get or use a macro lens for the first time is run an exposure test using different fstops at fixed magnifications. i.e. I shoot 1:2 magnification at F32,22,16,11,8,etc and determine and record the best fstop for that magnification. then do same thing at magnification 1:3, 1:4 etc. what I end up with is a chart that tells me the best fstop for each magnification. ======================================================================== ===================== In this case, with the SMC-M 50mm f4.0 lens I got MAG Fstop (best) 1:2 overexpsoses, out of fstop range 1:4 F32 1:8 F22 1:12 F16 1:16 F11 Now all I do is save the chart until I memorize it via repeated usage and I never have to fool around with my macro exposures, this saves a LOT of time. What I do is select a magnification to use based on the size of the object/target, set the fstop per the chart I created, and instead of focusing the lens to the target, I move the camera in and out while leaving the focus/magnification fixed as selected. The reason I do this is because if you focus the lens you are changing the effective fstop, by not focusing the lens, this variation is eliminated. I get beautiful consistant MACRO WITH FLASH exposures this way, very fast, and very easy. (warning - the fstops table for this lens looks like some sort of mathematical sequence, its not, its just conincidence in this case. with a 100mm lens you get a totally different sequence) JC O'Connell hifis...@gate.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.
