Lens with the largest f-stop for M9...any make

[dpattinson]

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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

 

Yeah, I'm not sure either...

[luigi bertolotti]

Of course, a longer lens has greater magnification... which will increase the effect of motion blur - I think?

 

Uhm... someway tricky... but my idea is that if you use a longer lens with the SAME magnification (farther from the subject) the motion blur is the same from the object in the focus plane, it is greater for a subject in background, smaller for a subject in foreground (ignoring focus issues, i.e., supposing both within the DOF zone: this question, probably, makes the difference in motion blur a pure theorical issue)

[pop]

The thing which determines motion blur is the angular speed of the object or - rather - the distance crossed by the image of the object on the receptor during the time of exposure.

 

Hence, if two lenses project images of the same size onto the receptor, the motion blur will be the same (all other things being equal, of course).

[adan]

It seems like this is getting uncessarily complicated:

 

To stop motion, use a fast shutter speed, or a short flash duration. Shutter speed can be ignored if the primary light is the flash (but may require keep the ambient light very low)

 

Some flashes have direct access to "speed" - others use a thyristor circuit that quenches the flash, cutting the "exposure time" short. Some strobes can produce exposures as short as 1/1,000,000 second. How and Why to use High Speed Strobes - High Speed Photography & Photographic Equipment | Woods Electronics Inc.| Shutter-Beam | ADDjust A Sec.

 

A short exposure time requires (or allows) the use of a large aperture or f/stop - and vice versa.

 

(For the record, a LARGE aperture is f/1 or f/1.4, a SMALL aperture is f/11 or f/16 or f/22. That "/" between the "f" and the number denotes a fraction, and so, just as 1/16th of an inch (or meter) is SMALLER than 1/4 of an inch (or meter) - f/16 is a SMALLER aperture than f/4. If you are using the terminology any other way, you are confused (and confusing) and wrong.)

 

The lens with the LARGEST aperture that can be fitted to an M9 is either the Canon 50 f/0.95 from the 1960's or the new f/0.95 Noctilux 50mm.

[pop]

It seems that we now can answer all questions about the topic with the exception of the question in the first post.

 

Most statements by OP appear to imply that the flash or strobe is much too bright such that a small aperture (or an ND filter) is needed to throttle the light.

 

Most people posting to this thread appear to think that the flash or strobe delivers so little light that a large aperture might be needed.

[rob3rt5]

Sorry for the confusion. I meant to say the smallest apeture. Thanks for the clarification.

 

The reason I asked the question, also to add some clarity, was that I have sold all my other equipment and only have an M9 at my disposal now. I would rather like to use it for everything and stretch my creativity than buy another studio camera and would like to freeze the motion of water while models are also in motion. I want to make sure I'm using the right strobes (Broncolor) and the right lens for the job instead of setting myself up for a very costly mistake.

 

After some research on the subject I discovered that a smaller f-stop might be needed in order to control overexposure when working close to the light source. Another variable is flash duration. I thought these were my only options.

 

Thank you for pointing out that a ND filter can also be used.

 

With that said- which would degrade the quality of the image more:

ND filtration or older lenses (my guess would be ND filtration but I don't know if I can achieve my goal with it)

[jaapv]

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With Leica lenses on an M9 in a studio setting any lens that you stop down beyond f 5.6 would degrade image quality more than an ND filter due to diffraction, regardless of the age of the lens. The only reason to stop down more would be the need for a deeper DOF. Otherwise use ND filters, either in front of the lens or (better) for the flash units.

[rob3rt5]

I understand Jaap- and thank you.

[rob3rt5]

I'm unfamiliar with ND for PARA which is 5' and some change wide at it's business end. Is there some product i'm not aware of that does this? ND for the lens then- right!

[luigi bertolotti]

You say you have a Broncolor... I am sure to have seen set of filters for Broncolor's lamp units - including gray/ND filters.... maybe have even a brochure with them, somewhere at home...

[pop]

Thank you for pointing out that a ND filter can also be used.

 

Depending on the situation, increasing the distance between the flash and the object might help as well. Not counting bounced light, the brightness is reduced by the square of the distance.