Working with LF lenses / Shutters

[greg_miller8]

I am a LF newbie and have learned much already from this board. I

have 2 questions for now about LF lenses (I am working with a

Horseman FA and Rodenstock S 150 f5.6 and Nikkor 90 f8).

 

1. When mounting your lens into the camera, do you orient the

controls (f stop, shutter speed,...) facing up or to the side? I

have been mounting facing up but find I struggle to read the settings

when my tripod is fully extended due to the height of the camera.

I'm wondering if it would be better to orient to controls so that

they face to the side (photgrpaher's right, perhaps?).

 

2. I'm nervous about exposure control since the f stop settings do

not have any detents and the scale is so small. If I want to bracket

(say under by 1/2 or 1/3 stop) it seems difficult to me to do this

with any precision. Am I missing something or is it just part of the

deal with LF?

 

Thanks.

[john_kasaian1]

Greg---

 

1) Sideways works for me, just be sure the cable release dosen't dangle in front of the lens (most lens boards are designed to fit on in one direction only, so this is an interesting issue!) 2) Bifocals, pal, bifocals!

[audidudi]

RE: 1) Modern shutters should operate properly when oriented in any direction. If having the controls on the side instead of on top works best for you and your camera, then so be it. 2) This is just part of the deal with LF. If this really proves to be a problem for you, then Horseman makes an exposure meter that will slip under the ground-glass and you can use this to precisely bracket your shots by watching the meter readout while you adjust your f-stop. While they are costly new, used ones turn up on eBay fairly regularly (although you need to be careful to buy the more recent version as the older ones use obsolete batteries that are difficult, if not impossible, to find these days).

[james_driscoll2]

Most LF lenses (modern) have an additional scale on the bottom

of the lens for the explicit purpose of seeing your shutter speed

and f-stop when the camera is high up in the air.

 

Sideways sounds fine in theory, but I would rather close the

shutter on the side than on the top, plus Its rather akward to cock

the shutter when it is on the side.

 

if you want f stop detents- get a compur shutter.

[leonard_evens]

It doesn't matter to the shutter how you orient the lens, but it might to you. You want to be able to see the aperture and time scales clearly and you want the cable release to be oriented conveniently. Some lenses have two aperture scales, 180 degrees apart, which makes things a bit easier. All my lenses have 1/3 stop marks but no detents. You ought to be able to get within 1/6 of a stop accuracy, and that should be more than good enough. I think it is a fantasy to think you can see differences smaller than 1/3 stop.

 

With b/w films or color negative films, exposure is not that critical, and overexposing slightly will deal with any uncertainties. With reversal film, exposure is more critical, and the conventional wisdom is that it is best to expose so the highlights are right (Zone VII or VIII) and if necessary underexpose slightly with respect to the shadows.

[www.naturesfinestimages.co]

Greg,

 

Here's something to try concerning your question #2. This has saved me dozens of trips and tons of film. If you're only bracketing 1/2 to 1/3 stop with 4x5 or 8x10, take two of the identical exposures. When you go to the lab, only develop one of them. After looking at your results from the first exposure, you can push or pull the second one in the lab to nail the exposure dead on. One thing I should mention from trial and error is to be absolutely sure to label your film holders immediately after you take the shot in the field! Good luck with your LF!

 

http://www.naturesfinestimages.com

[michael_briggs2]

<p>1. Orient the shutter whichever way is most convenient for you on your camera.</p>

 

<p>2. It is easy to set the shutter controls to 1/3 stop accuracy. Precision of this level in photography is a chimera anyway: light meters and shutter speeds are no more accurate. Most lenses, other than ones with long focal lengths long for the format, deliver illumination that varies from center to film corner by more than 1/3 of a stop. For the photography writers who say that 1/3 of a stop exposure accuracy is required for transparency film: I want to know whether it required for the center of the film or the corners? Many scences have more variation in illumination than 1/3 of a stop.</p>

 

<p> A similar question: <a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=005UdE">Exposure adjustments to within sub-stops, possible?</a></p>

[tony_galt]

You can orient the shutter anyway you would like that is convenient, but you may find that there is a little pin that sticks out of the back of it that mates with a slot in the lensboard, which prevents you from turning it. It is permissable to take the lens off the lensboard and remove that pin.

[robert_cardon]

MB -

 

�For the photography writers who say that 1/3 of a stop exposure accuracy is required for transparency film: I want to know whether it required for the center of the film or the corners? Many scences have more variation in illumination than 1/3 of a stop.�

 

You point is well taken, but I guess I don�t have that much fall off on my lenses. I can see a difference of 1/3 stop on 4x5 chrome film when I bracket. Normally I only bracket 1/3 stop if I�m quite certain about the ballpark exposure. You are correct in the lumination range; I�m talking about a base exposure. Now for B&W, 1/3 stop difference is probably not enough of an exposure variation to make a meaninful difference???? But then again �.

 

RJ

[ernest_purdum]

The little pin is there to keep the shutter from rotating while you cock it. Rather than remove it, you could get a cheap set of needle files, (one source is www.harborfreight.com) and file a little notch to clear the pin.

[pvp]

The little pin that sticks out the back of some shutters is there to keep the shutter from turning, not just when cocking the shutter, but mainly when tightening the flange on the back of the lensboard. Rather than removing a part with a purpose, why not just fix the lensboard to use the pin?

[jim_galli4]

LF precision is what drives the pedantics into the funny factory. There isn't any. If you test your shutters you'll find that the speeds can have more tolerance than the 1/3rd stop you're looking for. I have many older shutters (OK mostly US made, the copals are an improvement) that you can sit and watch the play when you change directions and start going back the other way, and 1/3 stop is about where the aperture starts to move again! You've got nice new stuff so you should have the best possible scenario. For chromes that are important to you, taking 2 identical shots for a possible push/ pull on the second is the next best advice to just learning how to use that spot meter and predict exactly what you'll be getting. For that you need a trash dumpster. When it gets about half full of crummy exposures you'll be the one giving the smart aleck answers here.

[capocheny]

Greg,

<p>

Getting down to the 1/3rd stop for transparencies suggests that you need to know

the effective speed of the film as well as knowing the accuracy/inaccuracy of your

shutter.

<p>

So, the best strategy is to firstly, test your film(s) to ascertain the correct speed in the

first place. Secondly, have your shutters CLA'd by a competent technician. Lastly,

follow the advice of some of the above posters.

<p>

Hope this makes good sense to you...

<p>

Welcome to the club!

<p>

Cheers<p>

Henry

[michael_briggs2]

<p>Robert, I don't know which lenses you are using, but all lenses have illumination falloff off-axis. The effect is reduced for long lenses. </p>

 

<p>As an example, take the very popular 150 mm focal length and the latest model, the Apo-Symmar-L. The <a href="http://www.schneideroptics.com/photography/large_format_lenses/apo-symmar-L/">datasheets</a> are available from Schneider's website. For a specific example, consider a photo with 4x5 film in landscape orientation and 20 mm of front rise -- nothing exceptional or stressing the lens. The corners of the film are either 66.0 or 90.3 mm from the optical axis. The distance 90.3 mm is u/u_max = 78% on Schneider's Relative Illumination graph. Reading the illumination from the upper solid light curve (for infinity and f22), the falloff is almost 1 stop. The theoretical prediction (cos theta to the fourth) is an relative illumination of 0.54, which is a falloff of 0.89 stops.</p>

 

<p>With transparency film, you may be able to detect one third of a stop differences in the base exposure. If the scene had grey cards scattered about, you couldn't meter the grey cards and control all of their exposures to 1/3 stop -- grey cards images on the corner of the film would receive almost a stop less light than the card at the center. Photographers rarely notice this effect and I think the meaning is that our materials have more exposure latitude than we sometimes think.</p>