Lens with adequate coverage with 6x9/6x12 roll film backs.greenspun.com : LUSENET : Large format photography : One Thread
I need some advice from all the LF experts on the site.
I am using a Wista 6x9 roll film back on my new Canham 4x5 DLC. I want to use a wider lens than my current 75mm Nikkor SW. I am considering several lenses in the 45-47mm range, solely for use with the 6x9 format, and possibly a 6x12 roll film back in the future.
I am getting some conflicting advice. I have been advised that the regular 47 f/5.6 Schneider SA does not have have sufficient coverage for the 6x9 format. Some folks have told me it affords very little possiblity of movement, and it has significant light fall-off at the edges, requiring a ND center filter. Others say the opposite.
I've also been told that the newer, more expensive Schneider 47 5.6 XL SA needs a center filter as well with the 6x9 format, even though the coverage afforded is significantly more than the regular Schneider 47mm f/5.6. I would think if the coverage were sufficient for up to 4x5, the XL would not require a center filter.
Additionallly, several sources have advised using the Rodenstock Grandagon 45mm, instead of either Schneider 47mm. They claim it not only has sufficient coverage/movements, but, surprisingly, it does not need a center filter with the 6x9, and larger 6x12 format.
Do any of you have any personal experience/thoughts on these lenses with the roll film formats? Thanks for your help, Sergio.
-- Sergio Ortega (email@example.com), August 05, 1999
The need for a center filter has little to do with actual coverage...or to put it differently, a center filter won't correct for insufficient image circle. All wide-angle lenses show some falloff, some more than others, although they may cover the format more than adequately, and older lenses may cover but be very soft out in the corners. Use the manufacturers specs to determine whether or not the lens gives sufficient coverage, not hearsay. Those specs are for f22, and with most modern lenses the circle of good definition is about the same as the image circle. As for a center filter, that's according to what you shoot and taste. While a center filter may be "proper" and give even density all across the frame, if you routinely burn down corners you may prefer to not shoot with the filter. Modern Biogon types generally have less need of a center filter than other wideangle types. Examples...an older 47 f8 SA doesn't show useful definition 2/3 out towards the corners until f22, while a concurrent 47 f5.6 SA is somewhat better at equivalent apertures, and a modern 47 SA-XL shows good definition way out to the edge of illumination....and if you shoot Velvia and don't want darker corners, all would need a center filter.
-- John Hicks / John's Camera Shop (firstname.lastname@example.org), August 05, 1999.
As John says, if you shoot chromes, you'll need a center filter. My experiences with center filters and some modern lenses are like this: If the angle of the actual picture is 80 deg a cf with factor 2 (darkening one stop) is needed, if the angle is 90 deg, the factor should be 3 ( one and half stop). Sure the mfg of the lens will give more accurate data if needed.
-- Jan Eerala (email@example.com), August 05, 1999.
With a 47mm f/5.6 S.A you'll have enough coverage for 6x9 and some (but not much) movement, but you might lose the corners when you go to 6x12. You will want the center filter if you are shooting color. With the newer XL version of the 47mm S.A. you'll have enough coverage for 4x5. A C.F. is optional for 6x9cm format, but IMHO, necessary for 4x5 and probably for 6x12. No experience with the 47mm f/8 S.A. or with the 45mm APO-Grandagon, sorry. With your Canham you will need a recessed board for the 47mm. Keith Canham has told me that some people are using the 55mm APO-Grandagon without a recessed board but movements are very tight. And of course no recessed board is needed for the 58mm S.A. XL. In my experience, the Rodenstock Grandagons exhibit less fall off than the Super Angulons, but I'm sure there are people who feel the opposite. All of the above info above is from personal experience.
-- Ellis Vener (firstname.lastname@example.org), August 05, 1999.
You have lots of wrong advice.
1: all large format lenses from the Rodenstock 35mm 4.5 Apo Grandagon up cover 6x12 and allow movements 2: all modern large format wide angle lenses have light fall off due to co sine failure as the rays reaching the edges travel much further than the rays hitting the center of the film. 3: center filters may be necessary (depending only on YOUR preferences for all wide angle lenses currently made by all manufacturers. If you would like a detailed data sheet on center filters I would be happy to mail it to you in the U.S. as well as detailed data sheets on the Grandagons and Apo Grandagon lenses. Outside the U.S. your local Rodenstock distributor can send them to you. These are only available by mail and not E-mail.
-- Bob Salomon (email@example.com), August 05, 1999.
I'd like to provide further emphasis on a point that Ellis made regarding the need for a recessed lens board. Keith Canham will tell you that the closest the standards can be positioned is about 55mm apart. Hence, any lens of shorter focal length than 55mm will require some type of recessed lens board. I've set-up my Canham DLC with the Linhof style lens board adapter. Linhof recessed lens boards (there are several different models intended for different situations) are mighty cramped. They do work, but using a lens mounted in one of these can be a real pain.
The problems I've run into and solved include:
1) On some older Linhof recessed boards, the cable release holder mechanism interferes with the top sliding lens board latch on the DLC. This is because the Linhof design assumes that boards are attached with the very elegant pinch clip on their cameras. Canham uses a simple sliding latch which travels down and horizontally along the top edge of the lens board as you work the latch. The interference lies with the amount of horizontal travel. I believe the newest generation Linhof recessed boards have the cable release holder mechanism in a slightly different position which solves this problem (some of the older boards can be found used for a much, much lower cost than a new one ~$40 vs $300). The "fix" for this problem is to remove the cable release holder on the lens board and use a Pro Release wide angle cable release extension (part # 603007) directly connected to your shutter.
2) With a Copal 0 shutter, the Linhof recessed board does not provide enough "headroom" to allow the insertion and remove of a flash sync cord. Changing to a right angle mount sync terminal (like some Nikon lenses use) doesn't solve the problem in that the front lens elements interfere as well. There are three solutions to this problem. A) Hardwire an extension socket which can be placed on the flat front surface of the lens board. B) If your using a straight sync terminal, install a short sync terminal extension cable when putting the lens on the board. C) If your using a right angle sync terminal, you can take a short extension sync cable and shave down the plastic in the connector until it can slide onto the sync terminal. I personally use the third method because using the lens is difficult enough without always having a sync cable attached.
3) Finger space is somewhat limited for direct manipulation of the shutter and aperture. The solution - I sometimes use a pen or small piece of wood to manipulate the controls.
I don't have any experience with the Toyo style recessed boards which will also work on a non-Linhof adapted Canham DLC. I believe they are slightly larger, so most (or all) of the issues listed above probably aren't relevant.
-- Larry Huppert (Larry.Huppert@mail.com), August 06, 1999.
"2) With a Copal 0 shutter, the Linhof recessed board does not provide enough "headroom" to allow the insertion and remove of a flash sync cord. Changing to a right angle mount sync terminal (like some Nikon lenses use) doesn't solve the problem in that the front lens elements interfere as well. There are three solutions to this problem. A) Hardwire an extension socket which can be placed on the flat front surface of the lens board. "
The 001016 Linhof recessed board comes with a right angle synch adapter for a Copal 0 shutter.
You are confusing the older 001015 recessed board for Compur shutters. That board is discontinued.
-- Bob Salomon (firstname.lastname@example.org), August 06, 1999.