47/8 SA.Century/finder/focus?

[jtk]

<p>f8 never seemed too slow for 4X5, but it sure is for gg viewing on 2X3, even with a Toyo loupe. And in any case, the Century (2X3) flatbed focus is too crude for confidence. Jammed ALL the way back, focus is good at middle/infinity...</p>

<p>What I'd LIKE to do is use this thing with a viewfinder of some sort, scale focusing. But of course, "scale" with a 47 on that flatbed would be inherently imprecise.</p>

<p>As well, there's the question of WHAT viewfinder....I've cobbled up a wire frame that's very unsatisfactory (seems like optics would be necessary for any kind of precision)....</p>

<p>I'd welcome some suggestions, workarounds etc... I'd rather not invest in a SA-width optical finder. </p>

<p>1) has anybody home-built an good finder for SA width? Pictures & words?</p>

<p>2) has anybody been happy with a 47/8 SA on a Century? (I've got those beauties, plus a bunch of easier lenses). Maybe I'll surrender and sell, but I've always regretted it later, when I've dumped out of that format. Granted it's just a toy, but I've perfected the scanning etc....</p>

<p>My intention has been to make full use of 6X9 and this camera's rugged light weight. But I keep reverting to easier gizmos, such as my DSLR (sorry guys).</p>

[dan_fromm2]

<p>Clean your camera's ground glass. And when you put it back remember that the ground side faces the lens.</p>

<p>I use a 47/5.6 SA on my Century Graphic, find it very bright. Just tried to focus it at f/8, found it more than bright enough. Are you sure you're focusing with your lens wide open?</p>

<p>A clip-on finder for a 20 mm lens on a 35 mm camera will have the right field of view, but on a Century Graphic it will have parallax problems with near subjects.</p>

[thirteenthumbs]

<p>A trick that I used on an old 4x5 with a dim ground glass:<br>

I went to the nearby office supply and got a fresnel similar to<br>

<a href="http://www.officedepot.com/a/products/327016/Office-Depot-Full-Page-8-12/">http://www.officedepot.com/a/products/327016/Office-Depot-Full-Page-8-12/</a><br>

cut it down to the ground glass size and attached it in front of the ground glass without moving the ground glass mounting position. Put the ribbed side of the fresnel next to the ground glass. It may improve the GG viewing enough for you.</p>

<p>Use a pexiglas cutter and straight edge or put masking tape on the smooth side of the fresnel then cut with a metal cutting blade in a variable speed jig saw on low with the fresnel held firmly. A straight cut router bit in a Dremel can be used to make a lip on the fresnel if needed. </p>

[dave_s]

<p>John, I use a 47/5.6 SA on my Century but I also use it with the ground glass. It helps that I always use a focusing cloth of some sort, either a real one, or of the overhead black T-shirt-exposed midriff type (not a pretty sight).</p>

<p>I see your point in looking for a finder, because a Century with a 47 would be great for hand-held wide-angle photography. I believe people have used an accessory finder in this situation, from something like the 50mm lens on the Mamiya Press camera. I can't remember the details, but you should be able to find a reference to what this was. It would probably be a pain to locate, and expensive. Alternatively, you could use a 21 or 24mm finder from a 35mm camera, but that would have a couple of problems. </p>

<p>Keep us posted on what you end up doing.</p>

[jtk]

<p>Thanks for your various comments. I do have a properly mounted fresnel lens...</p>

<p>This is an f8, not 5.6, and as we all know that's half as bright and the corners are even more of a problem. </p>

<p>Focusing isn't the entire problem, framing's tough too...but yes, I'm nervous about infinity adjustment: Jammed ALL the way back, no further depth so I can't confirm that I'm all the way home...it does seem to work on film, but I can't visually confirm by racking back and forth over infinity... the focus of a Century is pretty crude with any lens, especially a short one (think about the importance of helicoil with only 50mm on a 35 camera.</p>

<p>The problem with a 35mm camera's 21 mm finder is that it'd need to be elevated far above the top of the Century box...maybe a couple of inches. Precision alignment would be tough.</p>

 

[dan_fromm2]

<p>John, as I told you, I just focused my 47/5.6 at <strong>f/8</strong> with no trouble. <strong>f/8,</strong> not wide open.</p>

<p>I understand why you think you need infinity stops to scale focus; you're mistaken. What you need for scale focusing is a fixed reference to set the front standard at. I suggest that you put the front edge of the front standard at the front of the inner rails. This will eliminate unintended swing and will save some focusing travel. </p>

<p>Remember, the 47/8 SA's flange-to-film distance at infinity is 50.9 mm and your Century's minimum flange-to-film distance is 34.9 mm. Putting the front standard as far back as possible sacrifices a lot of focusing travel for no good reason. I just set my 47/5.6 (flange-to-film at infinity 51.6 mm) up on a 2x3 Crown this way, had to move the rail forward to focus at infinity.</p>

<p>If you don't want to clean your ground glass, get a good new one.</p>

<p>Charles, an add-on fresnel should be put behind the GG. Putting it in front of the GG will guarantee that the GG is not in register with the film plane.</p>

[jtk]

<p>Dan, my ground glass isn't the problem, but as fresnel does reduce detail resolution of the gg, while brightening, maybe I'll remove it for a while.</p>

<p>I'm pretty experienced along this line, with all sorts of view and press cameras. This wouldn't be nearly as challenging with 4X5, where it'd be easier to view a large part of the image. 8X10 is easier still, one of the best reasons for that format.</p>

<p>Yes, I'd independently found the front/front arrangement you mentioned and yes, I made a mark for scale focus at infinity. Sorry, I erred by saying I had to jam everything all the way back.</p>

<p>In any case, "crude" is the right word for scale focus with a 47mm lens and crude is the word for Graflex flatbed focus vs helicoil (the reason Linhoff offers a helicoil lens mount for wide angle). </p>

 

[jtk]

<p>Dave, yes, I use a black double thickness jacket for focusing cloth. <br>

I adjusted my rangefinder for 150mm, very accurate. It was originally set up for an 80/2.8 Heliar, which was fabulous...I'm thinking of readjusting back to that.</p>

[dan_fromm2]

<p>John, if your Century has an original issue focusing panel with fresnel in front of the GG (that's how Graflex did it), you can't just remove the fresnel. This because removing the fresnel will move the GG forwards and put it out of register with the film plane. You'll have to (a) cut out all but the rim of the fresnel so that the GG's position won't change or (b) find a focusing panel made for use without a fresnel. Both types were made, they have the same casting number and differ only in the height of the bosses on which the GG/fresnel sandwich or GG alone sits. I have both types.</p>

[brian berry]

<p>John, I got my E2 Rolleiflex back into the front lineup by installing a focusing screen from a Mamiya RB 67. I cut it down, of course, easy to do with an Exacto knife, and carefully checked the focus with a second ground glass at the film gate. I don't remember if I had to shim or not. But I gained 2 to 3 stops in apparent brightness compared to the factory screen. The brightness of ground glass when the Centuries were made simply left a lot to be desired.<br>

All wides look dim in the corners...sad but true.<br>

An alternative plan: for many years on my 4x5 (including rollback work) I use the microfine groundglass made for the Linhof microscope adapter back, known as the Aristophot. Google this and you will see what the unit looks like. As furnished, the glass is 125mm square. I cut it down with a conventional glasscutter. The etched surface of this glass pops the image in and out of focus by contrast change in a way that no American glass I have ever used can approach. Additionally, it has a polished "X" from corner to corner, about 2mm in width, that permits me to focus on the aerial image anywhere on the X. Priceless. My f8 wides are easily seen on this groundglass. These backs come up on the infamous auction site from time to time, often in parts, and they are not too expensive.<br>

I can't help on the finder problem. Good luck to you.</p><div></div>

[brian berry]

<p>Oops, Goofed. Hre is the one that's intact, the preceding picture is about the way you usually see them.</p><div></div>

[jtk]

<p>Dan, thanks for the reminder. I'd have missed that.<br>

Brian, I remember seeing Aristophots cheap in a pile in a medical supply house a long time ago...<br>

...as to fine focus, are you referring to the nearly clear part (seen in the X shape in your photo) or the more coarsely ground part?</p>

[brian berry]

<p>John, the ground part of the aristophot glass is crisp and bright. The polished part is very bright. Actually you are seeing an aerial image there, the brightest that can be had in any viewing system. I focus with a loupe on the border between ground glass and polished -- very fast and very certain. To view the whole image I pull back (to bifocal range, sadly, under the darkcloth.)</p>