Please, explain me the lens shutter...

[mva]

<p>Hello photographers!<br>

I am not new to my Bronica SQ-A, however there are still things that I do not understand. I wonder if you could help me with some explanation.<br>

There are two things that I miss, probably because they are strictly related in the SQ: long exposures and flash photography.<br>

I read in the manual that flash will sync at all shutter speeds, thanks to the lens shutter. But what is a lens shutter? I believe it is the aperture (diaphragm) that stays closed, then it opens at the desired aperture, then it closes back. However, if I am correct, how can I see through the viewfinder the image? Obviously the lens shutter is normally open. I am missing something.<br>

Then, I really do not understand the thing about Time Exposures. I know that I often use the Zenzanon on my Sony NEX, via an adapter, and that in order to keep the aperture set to the value, I have to shift the lever. However, I really have no understanding of this for a normal operation on the Bronica. They certainly did not insert this lever for use on other cameras via adapters! Could you please explain me what happens with time exposures?<br>

Thanks!<br>

Marco</p>

[gregory_king1]

<p>Most (if not all) lens shutters (also known as leaf shutters) are located NEXT TO the aperture, but are different pieces of equipment. <br>

<br />Yes, the shutter stays open during SLR viewing. The aperture also stays open, or closes down to the desired aperture for DOF preview. Automatic cameras leave the aperture open to make focusing easier and more accurate.</p>

<p>So, prior to exposure, many things happen. The shutter closes, the aperture sets to the correct diameter, and the mirror moves out of the way. Only now is the film "seeing" the back of the lens. Then, the shutter opens and closes for the correct duration, exposing the film. </p>

<p>On Mamiya, you have to recock the shutter and mirror to return to a viewfinder image. The mirror has to move down to protect the film before the shutter can reopen.<br>

<br />No help on the Zenzanon...sorry. :-)</p>

[dave_thomas8]

<p>Gregory has it correct as to the lens shutter. Unlike focal plane curtain shutters in many 35 mm SLRs, the Bronica lenses have a leaf shutter in the lens for timing the exposure. That is separate from the aperture blades. When the lens is used on the SQ series cameras, the steps Gregory describes are handled automatically. After the exposure you have to manually turn the crank to advance the film. That will lower the mirror and open the lens aperture and shutter for using the viewfinder.</p>

<p>I think the lever you are describing to set the aperture is actually considered the "depth of field preview." It's a little slider that closes the aperture mechanism to the opening set on the lens barrel. That is for the convenience of the photographer. When viewing, the aperture is normally wide open. When the actual exposure is made on the Bronica, the aperture closes to that setting automatically.</p>

<p>For time exposures, there is another control on the lens barrel, on the PS series lenses there is a silver stud to pull out to enable the slider to move from showing a white 'A' to a red 'T'. I believe that control is slightly different (a screw) on the older S series lenses (I only own PS series). When the slide is moved to 'T', the shutter will open when the shutter release is pressed and stay open. This happens regardless of the shutter speed setting. To close it, you move the slide back to A. I would tend to put a dark hat or something over the lens before closing so shaking the camera won't show in the exposure.</p>

<p>Hope that helps.</p>

[q.g._de_bakker]

The separate, mechanical way to set "T"ime exposures is offered because doing it this way does not use (and thus drain) battery power, while using any other speed will.

[rodeo_joe1]

<p>Sorry, was going to post animation, but computer says "no"!</p>

[mva]

<p>I think I have it clearer now. Thanks for all the explanations.<br>

To recap, what I have learnt now and was not sure before:</p>

<ul>

<li>in order to use flash sync at all speeds I don't need to do anything particular (such as time mode etc); it is always so with the SQ.</li>

<li>The "T" is only useful for long exposures, and nothing else (apart from adapting lenses on other cameras!)</li>

</ul>

<p>For some reasons I thought that in order to use the leaf shutter, I had to change mode. I thought before that when I heard the mirror slap, I also had a curtain shutter operating.<br>

thanks!</p>