john_lorenzini Posted January 29, 2008 Share Posted January 29, 2008 Hello, I'm trying to shoot at night in the city with a model. Because I want to shoot film and have a larger negative I'm using a Mamiya 645AFD with an on camera flash. However I'm having issues with the auto focus. Its not responding quick enough and often readjusting when I'm ready to take the shot. I don't have a lot of experience with this camera but from what I've experienced it cannot handle quick focus under low light situations. Whether I use the continuous focus mode or single focus there remains an issue. Although, what I'm doing seems more suited to a 35mm or digital equivalent but I'd like to avoid reducing my image quality and print size. Please help me with any information regarding the performance record of the Mamiya 645AFD's auto focus or lens performance. I'm using a 80mm 2.8 lens and shooting at 2.8. Basically tell me why the focus is slow or just not responding well enough under low light? If my subject is in motion at all it will also keep the camera guessing. Would a H1 perform any better? What I'm trying to capture can only be done hand held with an on camera flash, only. Thank You John Link to comment Share on other sites More sharing options...
volker_hopf Posted January 29, 2008 Share Posted January 29, 2008 Hi, I have a Mamiya AFD for a month now and am not winning with respect to Autofocus. It is just the way it is designed that makes it pretty useless. I have given up for the moment and will use manual focus when I get my microprism screen tomorrow. Sorry to be of not much help! Volker Link to comment Share on other sites More sharing options...
neil_colton Posted January 29, 2008 Share Posted January 29, 2008 In low light, and especially very low light, you will simply need to focus manually. Good luck! Neil Link to comment Share on other sites More sharing options...
dale_edward Posted January 30, 2008 Share Posted January 30, 2008 Hi John, Your situation with the autofocus hunting in low light is a dilema that will plague most auto focus cameras. The majority of autofocus cameras have a internal sensor which measures the difference in contrast within a specified area of the viewfinder. Unless the software in your autofocus circuitry is able to measure a difference in contrast between objects, the autofocus will not work reliably if at all. Try using autofocus on a white wall or a blue sky. The autofocus won't function because there isn't a big enough difference in contrast to be measured. I'm not familiar with your particular Mamiya's autofocus capability, but I do know that the newer Mamiya 645 AFD 2 has an improved autofocusing module. My suggestion would be to tripod mount your Mamiya 645 and pre focus the locations where your model would be situated. Manual focusing in low light can still be a challenge for even the best pair of eyes, so perhaps you could establish your pre focused points during the day. Dale Link to comment Share on other sites More sharing options...
alex_leonhardt Posted January 31, 2008 Share Posted January 31, 2008 Ok, here's an idea that sounds lame, but have seen people really using it to get the auto focusing right ... use a torch light ! :) you'd need a 2nd person for this, but well ... it's a "workaround" ;) ... hope it helps! Alex Link to comment Share on other sites More sharing options...
ron_miller5 Posted March 11, 2008 Share Posted March 11, 2008 Torch light? Hmmm, I just picked up a red laser pointer from Staples a few days ago to try this. read about it somewhere... Link to comment Share on other sites More sharing options...
jeffrey_blake_adams Posted March 15, 2008 Share Posted March 15, 2008 Flashlight, car headlights, anything. Link to comment Share on other sites More sharing options...
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