</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (jansenh @ Apr 16 2003, 02:52 AM)</td></tr><tr><td id='QUOTE'>
The question is: will a 100mm f4.5 lens on a 645 negative give a DOF that is narrow enough for portraits? The closest focusing on this lens i 6 feet. I don't need getting any closer and I have no problems imaginig the framing with this lens. It is the DOF that is big issue here.
The pictures I will take is typically a tight vertical aligned crop with two persons - on a beach. The water and horizon will be the background - there is no disturbing elements - I still want the background as blurry and OOF as possible. If the sun and the weather stand by me, the background will be high-key bright white and hopefully blurred out.</td></tr></table><span class='postcolor'>
DOF will depend greatly on the aperture.
If you use the 100mm wide open, you will not have much DOF... what film/filters/ etc. are you planning on using?
Normally, there will be a LOT of light on a beach, not only that reflected from sand and water, but due to the abscence of shade.
I'd suggest a trial run ... and *slow* film and/ or neutral density filters... also one of the "center-spot" or similar filters (I have a few jury-rigged - black "veiling" and sundry other materials sandwiched between two 'UV" filters). That should serve to obscure the background if not throw it out-of-focus.