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This was going to be a simple question: What is the name & catalog number of the Rodenstock Depth of Field/Tilt/etc. calculator gizmo?
But I've decided to complicate it. Has anybody actually used this gizmo and does it work and how well does it really work? Thanks for your help!
Ellis, go to the technique category and find the thread called Depth of Field Calculators/Aids. The poster there has used it and was not particularly impressed.
Funny how opinions vary.
Bob Wheeler in his comparison of calculators likes it. Pop Photo likes it, We have had no complaints about it. But not everyone will like everything.
The catalog number is 260700 and it is the Rodenstock Calculator.
Re-reading the poster's comments was that he found it confusing.
Of course each step on the calculator is numbered and you simply follow steps 1 to 4 to set it up for depth of field and pointer 5 gives f stop and pointer 6 the exposure correction.
That is a bit complicated I suppose.
Steps 1 to 4 are:
1 Is the camera tilted and, if so, how much? 2 Format being used between 35mm and 4x5 3 Reproduction scale you are shooting at 4 Distance on the focusing rail between the near and far point (a MM scale is on the calculator to determine this)
Sounds as complicated as the poster stated?
The other side of the calculator is equally complicated as it computes Scheimpflug.
Again by following numbered steps. But this time there are fewer. 5 steps. 1 to 3 to set up the calculator and 4 and 5 to read it.
1 Is the camera level or inclined and, if so, how much? 2 Distance between the near and far points on the ground glass 3 Distance between the near and far points on the focusing rail
4 What was the angle in step 1 above? 5 Read the required tilt angle against scale in step 4
That is exactly how "complicated" the use of this calculator is in operation.
Every step on both sides is clearly numbered. It isn't very difficult.
Sorry a major correction.
The calculator is for formats from 35mm to 8x10" not to 4x5" as I stated earlier.
I have the calculator, and use it. I do find it to be confusing and I occasionally have to refer to the instructions printed on it. However, I view this difficulty as the trade-off for having this information available in such a small and durable device.
One thing I wonder about is how does one exactly know what the incline angle of the rail is or the incline of the focusing plane? My ballhead (Linhof 3) certainly doesn't have any markings on it, and to compute the incline of the focusing plane, you'd need some rangefinder device to measure distances precisely and then compute the angles with an electronic calculator. Furthermore, if you carry an electonic calculator, you may as well program the DOF formulas into it and compute it directly.
Weeeelllll, I'm not taking sides mind you, but if you don't mind spending $5.00 and carrying maybe .6 pound extra, you could stop by the hardware store and buy a circular angle level and butt that up against the g.g. to determine the angle off of plumb of the camera.
Or, you could use your mental protractor and estimate. 90 degrees is pretty obvious. 45 is half that, 22.5 is half that and 11.25 is half that.....
5 degrees of tilt is not negligible in many cases. However, I definitely cannot estimate the 5 degrees ... Do you know of a cheap and small level I can buy that will read to within 1 degree increments?
Like I said, go to the hardware store and pick one up. I think mine cost about $5.00 from True Value. It's 2" on a side and reads in 1 deg increments all the way around. The hash marks are teeny-tiny but they're there.
Calumet used to sell a similar device for $70.00 (=/-) and recently a kit from one of the photo suppliers came up for auction on E-bay. it had an angle finder and bellows extension "calculator" in one nice flat light kit.
Personlly, I don't see why one couldn't use their eyes on the ground glass and Polaroid. Folks have been doing it that way, and without Polaroid long enough, Heaven knows.
O.K., Calumet carried it, it was made by Horseman and it cost $74.99. Catalog # HR1015 in the 95-96 catalog. It was called the photo angle finder and was accurate to within 1/2 degree. It's not listed in the more recent Calumet catalog and the B&H Professional Photo Source book has it listed as discontinued.
The one I got from True Value was $9.49, not $5.00. At those prices, no wonder Horseman discontinued it.
RE: "Do you know of a cheap and small level I can buy that will read to within 1 degree increments?"
Horseman made a wonderful Photo Angle Finder (wasn't so inexpensive, but accuracy and precision rarely comes at low cost). It even had a mirror behind the needle so you could read it with consistent accuracy. In their infinite wisdom, they came out with a new version of the Photo Angle Finder, and replaced it with a nearly worthless (IMHO) hunk of plastic with less accuracy and more difficult to use.
I've also used the Rodenstock calculator, and find it an OK tool in a limited way. I wish I knew some of the assumptions it has built in like the circle of confusion for different formats. I find the Depth of Field side of the calculator more useful than the Scheimpflug calculator side. I've rarely been happy with the tilt angles it calculates and ultimately find trial and error easier, more accurate and faster. At best, the tilt angles are a starting point.
I have this calculator too. I completely agree with Larry. I think Ellis is looking for a calculator for his DLC.
The depth of field side is more useful than the opposite side for angle finding. It is because you need to know <ul> <li>the angle &Alpha between the optical axis and the monorail <li>the vertica distance (horizontal distance for swing) on the ground glass between any two points on the focus plane <li>the angle &Beta between the optical axis and the desired focus plane </ul> And finally you get the tilt angle &Gamma on your camera. It's much faster to figure out &Gamma using try and error with educated guess work by yourself. All we want to know after all is &Gamma. If we can figure out it, why care about especially &Beta (&Alpha is useful to determine the depth of field necessary)? Above all, it looks like the calculation for &Beta is designed for a camera with center tilt. Somebody any comment?
Depth of field side is useful because Linhof DOF table does not include &Alpha (i.e. &Alpha = 0; optical axis and monorail are parallel) or bellows extension factor (I have to check...). But of course if you set them parallel most of the time, I think you can fix the &Alpha dial at 0 degree by tape. IMO, the combination of Linhof DOF table and a list of Bellows extension factor for each of your lens is much quicker assuming you use &Alpha = 0 most of the time.
iCorrection for the above comment: Above all, it looks like the calculation for &Beta is designed for a camera with center tilt. I wanted to say &Gamma, not &Beta.
I have seen a lot of levels at many stores including the large Tru-Value HD store across my home. Interesting that you have found a cheap 2" level that reads to one degree accurately!!! I must be really missing something here because I don't think that is physically possible. Does it have a magnifier so you can see where the pointer is lined up? or is it one of those bubble levels with graduations that are very limited in the angular range they can measure?
BTW, everyone talks about tilt. How about SWING? Any bright ideas?
The company that made the circular angle finder I have is named Johnson. The price sticker says ServiStar. The package reads:
"Precision Angle Locator Measures angles instantly and accurtely from 0 deg to 90 deg ina nay quadrant. Accurate leveling and transferring of angles on any surface. Includes conversion chart for pitch per inch and pitche per foot."
Electrical Conduit
Machinery set-up
Pitch or slope
Roof construction
The device itself is black with a clear circular guage calibrated in degrees from 0 to 90 four times with larger hash marks every 10 and dots at key points 45 deg, 90 deg, etc. The circular dial is 3" across. There are two flat surfaces for setting the guage down on the surface you're measuring, one is 2" and 3.5" long.
As I said, it is calibrated in individual degrees but they are tiny and require you to hold it steady and look closely. I got it in case I'd need it and out of protest against the high price tag of the Horseman unit. So far an occassion for it's use has not occured.
Johnson's address on the back is Johnson Level & Tool Manufacturing Co. Inc. 6333 W. Donges Bay Road Mequon, WI 53092-4456 USA
I imagine you could find 'em in the ThomCat Register.
If accuracy is essential, why not get a SINAR or a Linhof or other camera with swing and tilt scales calibrated in degrees?
RE: "BTW, everyone talks about tilt. How about SWING? Any bright ideas?"
Why yes! Assuming you camera doesn't have any steel (which the Canham DLC doesn't to my knowledge), you can use a common magnetic compass. Measure before swinging, move the compass dial the number of degrees you desire, and swing the lens until your aligned back to north. The higher quality camping compasses will allow about 1 degree accuracy (some even have a built-in magnifier where you read the dial). For now, forget digital compasses. Their accuracy seems less than standard compasses.
Larry, YES! Why didn't I think about that?!
Carlos,
My Boy Scout compass is 1.5" across the dial and it's calibrated in 1 degree increments around the full 360 degrees. Is that physically possible? I'd think gravity was just as reliable as magnetism.
As for addressing the "how to find the angle of the plane of sharp focus" Well this to me is the most critical part of lens tilt. If you have that, you can then estimate the distance the plane of sharp focus interesects below the lens, then you only need to glance at a look up table (cheat aheet) to determine the tilt angle. You can sketch it out to be sure, some quick geometry. I use a Clinometer, with a sight scope in it, it tells you from where you are standing the height of an object and its angle. It is the size of a pack of matches. But I must admit, I carry a TI - 89 calc. with me anyway, it has the most amazing numeric solver program in it. You load an equation with all it varialbes, then enter all what each varialbe equals, and solve for the missing one. The beauty is, it does not matter which variable you are missing, it solves it with out you having to re write the equation for the missing variable... they are $159 at any office max.
That's a good point Sean.
This comment is somewhat drifted from the original question but if you're looking for an angle finder for both swing and tilt, any compass with clinometer does a decent job. I have a Suunto MC-G1 compass ($50-$60). Silva also makes similar ones. For accuracy, you might want to buy a Suunto Tandem. The cheapest I could find on-line is $160 at BEN MEADOWS COMPANY. But you need to look through the view finder to get ± 1/4° accuracy. So it's probably not practical and awkward to use this instrument on a camera. I think Bill uses an optical clinometer. Right?
I would say an angle finder as Sean says is as functional as Sinar angle finder on F cameras. A Sinar is not so compact compared to others for a field work. (I have seen a nice angle finder marked "Devil's level" in a View Camera Technique book.) The next practical would be an orienting compass with clinometer, which people carry in field anyway. The last might be an optical compass. If you have a plenty of time to shoot an object, this one is good. To me, a simple try and error with educated guess is the quickest in the field by sketching Scheimpflug and hinge lines in head or on a piece of paper if I get confused. I could easily miss the moment in field (especially when light is changing dramatically) if I'm looking at the angle finder, turning dials of the Rodenstock calculator or punching numbers in calculator.
Thanks everybody for your responses and suggestions.
I already use a large angle finder as an aid when copying artwork. It is a "#36 magnetic (the base has a magnet in it) Polycast Protractor" made by Empire. The base is about 4" long. it is easily readable in dim light and even has a sliding reference marker.
The previous suggestion about using a compass with a clinometer is interesting. This should work fine. I have such a compass (from Brunton), and the only problem is that the magnetic declination and clinometer use the same scale (as I remember, Silva and Suunto models were similar). What this means is that your always zeroing out the magnetic declination when you need to use the compass as a clinometer, and resetting the declination when you need the compass for navigation use (or using it to determine the orientation of a building). It's kind of a pain.
For the ultimate in tilt angle measurement, take a look at the Mitutoyo Digital Protractor model 950-316. For tilt measurements, it's accurate to +/- 0.1 degrees and for leveling your camera, it's accurate to +/- 0.05 degrees. The size is right as well: ~ 6" long x 2" high x 1 1/4" wide. I've only seen it in their catalog, and expect it is extremely expensive.
Scheimpflug would be amazed on how complicated his simple rule has evolved. Tito.
Larry, my Suunto compass adjusts the magnetic declination independent of the clinometer scale. So I do not have a problem you mentioned. Can't you read the angle from the bezel even for your compass?
When I was looking at compasses, I didn't find any which had magnetic declination independent of inclination. On the compasses I've seen, you could read inclination from the compass bezel, but not with great accuracy. I even looked at a fairly wide range of Suunto models. What I find interesting is that the most precise handheld compass/clinometer (like the Suunto Tandem) don't have any adjustment for magnetic declination. If you use programs like sunPATH this isn't a problem because they can be configured to factor out magnetic declination.
Correction for my first comment:
...Linhof DOF table does not include &Alpha (i.e. &Alpha = 0; optical axis and monorail are parallel) or bellows extension factor... IMO, the combination of Linhof DOF table and a list of Bellows extension factor for each of your lens is much quicker assuming you use &Alpha = 0 most of the time.
The Linhof table does have a list of extra stops for bellows extension, given a number G where "G = distance of diaphragm plane to the forward 1/3 of the subject" as quoted. In the Rodenstock, input magnification then you get extra stops for correction and effective aperture, displayed seperately. The Rodenstock DOF calculator is more accurate and easier to use than the Linhof table. In Ro, you can read the intermediate values of a stop, easily 1/6 stop whereas the Linhof table displays values in 1 stop increments. (It's the advantage of a dial calculator compared to a table with small set of numbers.) So a good combination would be Rodenstock DOF calculator and an aid to determine magnification (e.g. Calumet Exposure Calculator, Quick Disc, or using one of the methods described he re).
Does anyone know if something like this exists or if there is a phone app that does the Scheimpflug principle?
Hm, maybe a weird question: Why do I have to calculate the angles to apply a Scheimpflug principle? I mean - I do have the nice ground glass...
Another solution would be to attach two laser pointers (those tiny pointers with the red light) to the front and rear standard. Turn the standard(s) until both beams meet on the ground or at the wall or any plane you need your focus on. OK, they need to be calibrated on the camera, but that's just about an hour of concentrated work.
Yes, the Rodenstock Pocket Scheimpflug/DOF Calculator is a current item and is available from any of our dealers in the USA.
The calculator is not the final arbiter of camera movements.
It's designed to rough in the positions, particularly useful when you don't have subject features convenient for focusing.
If you can preset the camera angles, then focus on features that are available, you have reasonable confidence that the
remaining fine details (leaves, flower, etc) will be in focus.
- Leigh