rob3rt5 Posted January 18, 2010 Author Share #21 Posted January 18, 2010 Advertisement (gone after registration) Of course, I'll have to sell my house to finance the strobes. Link to post Share on other sites More sharing options...
Advertisement Posted January 18, 2010 Posted January 18, 2010 Hi rob3rt5, Take a look here Lens with the largest f-stop for M9...any make. I'm sure you'll find what you were looking for!
earleygallery Posted January 18, 2010 Share #22 Posted January 18, 2010 JPH1962 has got my drift. I want to use a Broncolor strobe with my M9 and not get motion blur and after looking at the charts and specs I realized that if the flash is quite close to the subject and one is using a large source light (Para w/ diffuser) one needs a rather small f/stop (f/22-64?) to control motion blur. How does the f stop control motion blur? The variables here are brightness/power of the flash (or distance from flash to subject), ISO and aperture. Shutter speed is irrelevant as stated above. Also as stated above if the smallest aperture still results in overexposure you can use a lower ISO (if possible) or ND filters. Link to post Share on other sites More sharing options...
Nicoleica Posted January 18, 2010 Share #23 Posted January 18, 2010 If I understand this thread correctly, then using ND filters will have the same effect as reducing the size of the aperture. However, another option would be reducing the flash output power. This should not increase the flash duration. Setting 1/4 power would have the same effect as going from f:16 to f:32 etc. Link to post Share on other sites More sharing options...
jaapv Posted January 18, 2010 Share #24 Posted January 18, 2010 There is another point too. A studio setup - a good tripod - oodles of good light - time to focus perfectly- those are the circumstances that will show up quality loss through diffraction. I would, in that case, never close down further than 5.6. Link to post Share on other sites More sharing options...
jaapv Posted January 18, 2010 Share #25 Posted January 18, 2010 If I understand this thread correctly, then using ND filters will have the same effect as reducing the size of the aperture. However, another option would be reducing the flash output power. This should not increase the flash duration. Setting 1/4 power would have the same effect as going from f:16 to f:32 etc. No, it won't increase flash duration, it would decrease it. Flash units generally reduce power by reducing flash duration. Link to post Share on other sites More sharing options...
JPH1962 Posted January 18, 2010 Share #26 Posted January 18, 2010 Was doing the research to buy the right pack for my only camera left (M9). Just sold my Hasselblad H3D-39 to fund it's purchase. I was looking at the A2 or a small Briese maybe. When you look at a 1600 Joule unit, you will always get around 1/250th s flash duration at full power with one head, if you use a twin tube head you will divide by 2 the duration. When you lok at a broncolor Pack where you can preset the flash duration you have a decisive advantage: With a PulsoA2 or Grafit A2 you could reach a 6000th s. It is important to bear in mind that the flash duration is shown in two ways: t0.1 and t0.5 - the ine important to consider is t0.1. On these you can change the output over a couple of f-stops. Link to post Share on other sites More sharing options...
dpattinson Posted January 18, 2010 Share #27 Posted January 18, 2010 Advertisement (gone after registration) I really don't understand the gist of your question. I can understand that if you have a powerful enough strobe setup, and that setup can reduce flash duration, then you would want as short a flash duration as possible to freeze motion (say 1/6000 as mentioned above). Typically that would mean a lower output from each individual strobe (same intensity over less time). To compensate (or to allow) for that you would seem to need to open up the aperture on the camera at a fixed iso, so that the reduced flash output would not result in underexposure. I really don't understand why you would need a small aperture (high f-stop number), and if you do - why that couldn't be mitigated by just using a ND filter? Link to post Share on other sites More sharing options...
JPH1962 Posted January 18, 2010 Share #28 Posted January 18, 2010 I really don't understand the gist of your question. I can understand that if you have a powerful enough strobe setup, and that setup can reduce flash duration, then you would want as short a flash duration as possible to freeze motion (say 1/6000 as mentioned above). Typically that would mean a lower output from each individual strobe (same intensity over less time). To compensate (or to allow) for that you would seem to need to open up the aperture on the camera at a fixed iso, so that the reduced flash output would not result in underexposure. I really don't understand why you would need a small aperture (high f-stop number), and if you do - why that couldn't be mitigated by just using a ND filter? you are right, fact is, that when working with such short flash duration, one never has too much power - and if that should be the case, one can put ND foils in front of the light or the lens... or just tune the lighting.. connect an aditional head to be fired off the set etc... As stated above, most flash units do not decrease their flash duration when reducing power - it increases! Concerned are the units that do not disconnect capacitors to reduce power, but the units that reduce the voltage aplied to the flash tube to alow output tunning. Example: a 3200 Joule pack at full power has around a 125th of a second - decreased by 4-stops it is only around a 1/70s. Small an cheap monoblocs often disconnect capacitors to achieve power reduction - you can recognize these by their rather simple settings possible (full / half / quarter power) - these units decrease their flash duration when reducing power. So you have two types: - Capacity switching (reducing flash duration while decreasing power) - Voltage regulation (increasing flash duration while decreasing power) To shorten the flash duration one can use a second head an the same pack or unse heads with twin tubes. well a whole subject by itself.... Link to post Share on other sites More sharing options...
dpattinson Posted January 18, 2010 Share #29 Posted January 18, 2010 you are right, fact is, that when working with such short flash duration, one never has too much power - and if that should be the case, one can put ND foils in front of the light or the lens... or just tune the lighting.. As stated above, most flash units do not decrease their flash duration when reducing power - it increases! Concerned are the units that do not disconnect capacitors to reduce power, but the units that reduce the voltage aplied to the flash tube to alow output tunning. Example: a 3200 Joule pack at full power has around a 125th of a second - decreased by 4-stops it is only around a 1/70s. Small an cheap monoblocs often disconnect capacitors to achieve power reduction - you can recognize these by their rather simple settings possible (full / half / quarter power) well a whole subject by itself.... OK, so in order to get a shorter flash duration, you will need to have a larger total light output. And in order to avoid over-exposure at close ranges, you want to stop the lens down? In that case why not put a 5-stop ND filter on the lens and effectively that takes your f.16 lens up to a f.512 lens (in terms of restricting exposure)? Link to post Share on other sites More sharing options...
ballyscanlon Posted January 18, 2010 Share #30 Posted January 18, 2010 at least on profoto 2400 packs and the broncolor 3600 packs that i work with regularly in studio, we adjust ISO or F stop when we are getting "ghosting" from a moving model, so we can reduce the power needed from the back so that the flash duration becomes faster. i know some people who specialize in shooting water, they use broncolor only (because it allows you adjust the flash duration manually for any given output. they shoot on tripod and exposure is 1 sec. john Link to post Share on other sites More sharing options...
JPH1962 Posted January 18, 2010 Share #31 Posted January 18, 2010 OK, so in order to get a shorter flash duration, you will need to have a larger total light output. And in order to avoid over-exposure at close ranges, you want to stop the lens down? That is only partly true, as the change is not really impressive... 3200Joules, 1 head = 1/120th or 4 heads = around 1/500th minus 1 stop... minus 4 stops = 1/70th or four heads around 1/250th so no big deal The same variation with a 1600 Joule pack would be from perhaps a 230th at full power to may be 1/150th four stops down. When using a sprobe pack such as a broncolor A2/A4 where you can set the t0.1 duration it is a diffent thing as the flash it cut off to the selected duration - the shortest here is 1/6000th at t0.1 and this is independent of the number of heads used. Link to post Share on other sites More sharing options...
dpattinson Posted January 18, 2010 Share #32 Posted January 18, 2010 So, I'm still confused then... Why would you care about the minimum aperture of the lens in this case? I can't see any reason why a vastly cheaper ND filter wouldn't work just as well... Link to post Share on other sites More sharing options...
JPH1962 Posted January 18, 2010 Share #33 Posted January 18, 2010 well... that is the point of the OP.... Link to post Share on other sites More sharing options...
jaapv Posted January 18, 2010 Share #34 Posted January 18, 2010 Not really, he had a feeling ND filters would not work as opposed to aperture. Link to post Share on other sites More sharing options...
likalar Posted January 18, 2010 Share #35 Posted January 18, 2010 JPH1962 has got my drift. I want to use a Broncolor strobe with my M9 and not get motion blur and after looking at the charts and specs I realized that if the flash is quite close to the subject and one is using a large source light (Para w/ diffuser) one needs a rather small f/stop (f/22-64?) to control motion blur. My 2 cents, with a couple questions... Is the Broncolor going to be the only light source? If so, the amount of "motion blur" of a fast moving object will be determined by the duration of the flash. (the camera flash sync shutter speed is too slow to stop most motions). If you can set the Broncolor for a very short duration, you are also likely reducing the light output of the unit. Reduced light output likely means you'll need a faster lens (bigger opening, not smaller) to get proper exposure. It also means you'll likely need the strobe light source placed closer to the subject, in order to get proper exposure. Is the Broncolor strobe going to be mixed with ambient light that you are trying to eliminate by using strobe? If so, you may need that smaller f/stop (along with Broncolor set for high output/longer flash duration) to purposefully underexpose the ambient portion of the mixed lighting. Best of luck. I hope this didn't add to any confusion. Larry P.S. Most of the high output strobe packs I've used did a lousy job of stopping motion when set at full power. That's because the high output is a partial result of making the flash last much longer. This increased length of flash time is counterproductive as far as stopping motion. If I remember correctly a 2400 Speedotron pack (full power with one head) had a duration of maybe 1/125. Tons of light, but lousy for stopping motion. Link to post Share on other sites More sharing options...
dpattinson Posted January 18, 2010 Share #36 Posted January 18, 2010 well... that is the point of the OP.... I thought the OP was looking specifically for the lens with the largest settable f.stop that would mount on a M9. Given that the ND filter solution seems pretty obvious, I assumed that the OP had a specific reason for preferring a small aperture. I guess I assumed incorrectly, but I thought there might be some property of smaller apertures in this scenario that I was missing... but I guess not So my answer to the OP would be - buy the 'cheapest' Leica M lens that has the appropriate field of view and put a ND filter on the front once you've tested and determined what power ND you need. I wondered if what the OP referred to as motion blur, was actually DOF blur since close ranges are mentioned? In that case, you would want a lens that stops down... but much further than f11 on a M lens is going to be introducing diffraction blur to offset the increased DOF... Link to post Share on other sites More sharing options...
bill Posted January 18, 2010 Share #37 Posted January 18, 2010 As someone to whom flash is first and foremost a floor cleaner, I am reading this with interest, and learning a lot. However, being the simple bugger that I am, I am exercised by two simple questions to the OP: 1. Why? and, perhaps more trenchantly, 2. Why with an M9? Regards, Bill Link to post Share on other sites More sharing options...
UliWer Posted January 18, 2010 Share #38 Posted January 18, 2010 I admit that I do not really understand the purpose, though I think the OP is looking for a lens with minimal aperture. Therefor my advise would be looking for old lenses with longer focal length. The original 4/90 Elmar could be stopped down to 1:1/36, the later one - post war - to 1:1/32; same for the 4.5/135 Hektor. They are normally screw-mount lenses, but can be used easily with an adapter on the M9. Link to post Share on other sites More sharing options...
dpattinson Posted January 18, 2010 Share #39 Posted January 18, 2010 Of course, a longer lens has greater magnification... which will increase the effect of motion blur - I think? Link to post Share on other sites More sharing options...
jaapv Posted January 18, 2010 Share #40 Posted January 18, 2010 Ummm... with the same subject enlargement as a shorter lens? Maybe not, at least the subject itself. That is disregarding perspective and blur in fore- and background, of course. Interesting twist. I must think this one through Link to post Share on other sites More sharing options...
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