First Large Format (Ignorance and Expense)

Sharktooth · Dec 13, 2022

There's a good description of this left knob from a posting years ago on Photrio. Sinar Calculator

It's an interesting concept, and could be used on any camera quite easily. I have to give credit to Sinar for some ingenuity here. Just draw any two horizontal lines on the ground glass, one below the center axis, and the other above. Focus on the one of these lines and note the focus scale position. Next, focus on the other line, and note the focus scale position of that one. The difference between the two positions is the focus travel between the two points (fore/aft). The up/down dimension is the distance between the two lines. The fore/aft and up/down dimensions form the legs of a right angled triangle, and the angle of the resulting hypotenuse is the tilt angle. It's just a simple math calculation.

Since the upper and lower lines on the Sinar ground glass are already fixed and known, the only variable is the fore/aft focus difference. The left side knob rotates with the fore/aft focus, so it's marked with the corresponding tilt required. Very smart and cheap. This is something you could jury rig on just about any camera.

I have a Sinar f, and it doesn't have this left knob, so I wasn't sure if the f2 was somehow different. All the Sinar f models have standard base tilts, so they're no different from the Sinar Norma in that respect. The Sinar P series is a completely different animal. You don't need a calculator to figure out the tilt angle since it's asymmetric within the film area.

John Patrick Garriga · Dec 13, 2022

Sharktooth said:
There's a good description of this left knob from a posting years ago on Photrio. Sinar Calculator

It's an interesting concept, and could be used on any camera quite easily. I have to give credit to Sinar for some ingenuity here. Just draw any two horizontal lines on the ground glass, one below the center axis, and the other above. Focus on the one of these lines and note the focus scale position. Next, focus on the other line, and note the focus scale position of that one. The difference between the two positions is the focus travel between the two points (fore/aft). The up/down dimension is the distance between the two lines. The fore/aft and up/down dimensions form the legs of a right angled triangle, and the angle of the resulting hypotenuse is the tilt angle. It's just a simple math calculation.

Since the upper and lower lines on the Sinar ground glass are already fixed and known, the only variable is the fore/aft focus difference. The left side knob rotates with the fore/aft focus, so it's marked with the corresponding tilt required. Very smart and cheap. This is something you could jury rig on just about any camera.

I have a Sinar F1, and it doesn't have this left knob, so I wasn't sure if the f2 was somehow different. All the Sinar f models have standard base tilts, so they're no different from the Sinar Norma in that respect. The Sinar P series is a completely different animal. You don't need a calculator to figure out the tilt angle since it's asymetric within the film area.

I don't think I understood a lick of that. I'll try and come back to it again at some point and see if I get it any more.

Sharktooth · Dec 13, 2022

You don't really need to worry about it. It doesn't necessarily offer any major advantage, but it does offer a different approach that might be useful. The Sinar ground glass already had the lines for use with the Sinar P, so this little feature made these lines useful for the Sinar f2 as well. The added cost for the little scaled knob was pretty insignificant in terms of the overall cost of the camera, so why not? It makes for a nice little marketing feature.

Note: I should clarify my previous statement that this methodology could be jury rigged on just about any view camera. This wasn't correct. The front standard would need a tilt angle scale to make this feasible. The Technikas, and most wooden field cameras don't have tilt scales, so this methodology wouldn't work. If your camera has a tilt scale, then you could probably make something to achieve this same function.

Donald Qualls · Dec 14, 2022

John Patrick Garriga said:
Wish there was some way you could get a digital back that mimicked film to practice on, something low res but just so I could make sure all of my exposures were correct

Hssss! Blasphemy! You just need cheap film -- and paper negatives will do that job. Another option is ortho litho film, which will produce continuous tone negatives in common film developers, though it's often denigrated as making inferior quality images -- but it *is* cheap. X-ray film is another option, but it's only cheaper than Fomapan if you recut it yourself from the larger sizes it's sold in (this can be done under red safelight, BTW). Then there are roll film holders, allowing you to make (for instance) eight 6x9 cm negatives on a roll of 120 for the cost of about two to four sheets of same brand 4x5, but still with all the "dance" of large format as well as ability to use movements.

John Patrick Garriga said:
Also, having trouble figuring out exactly what these knobs do. Bottom moves when I adjust my focus, is that supposed to help me find my focus again quickly when I lose it? Set it to 0 when I’m in focus and come back to it when I need to?
Top doesn’t seem to do anything. Can loosen it but nothing moves

Others have said what the marked knob does -- something Sinar specific that I don't recognize (never handled a Sinar). The unmarked one may just be a lockdown -- when loose, something can move in response to another control (focus?), and when tightened, that control is locked.

tih · Dec 14, 2022

Donald Qualls said:
The unmarked one may just be a lockdown -- when loose, something can move in response to another control (focus?), and when tightened, that control is locked.

It holds the standard's frame to its bearer, if memory serves.

Anyway, the manual can be downloaded from Sinar: https://sinar.swiss/support-en-us/downloads-en-us/

FotoD · Dec 14, 2022

If it's the same as on the Sinar P, it looks a lot like the knob for locking down the accessory rod (that holds a compendium or a filter holder). There should be a penta- or hexagonal hole where the rod fits.

John Patrick Garriga · Dec 14, 2022

Donald Qualls said:
...X-ray film is another option, but it's only cheaper than Fomapan if you recut it yourself from the larger sizes it's sold in (this can be done under red safelight, BTW)....

So does X-ray film have a special affect? I know it's supposed to be high ISO but is there anything else special about it that would come up in regular shooting?

Donald Qualls · Dec 14, 2022

X-ray (from my reading; I've never used it) ranges from ISO 12 equivalent to 100, depending on the film, the light, and the technique. It's popular among 8x10 and ULF users, because it comes in some of the same sizes. For 4x5, it has to be recut to fit the film holders. Many stocks have emulsion on both sides, and are very prone to scratches as a result; there can also be a "glow" around light sources because of this. Film Photography Project sells it already cut to 4x5, but after paying them to recut and repackage, it's about the same price as Fomapan or .EDU Ultra.

wiltw · Dec 14, 2022

Alan Edward Klein said:
Doesn't diffraction depend on the size of the print as well?

Diffraction being apparent or not -- like the Circle of Confusion being 'blurry' vs, 'sharp enough' -- is entirely dependent on magnification to attain print size, viewing distance of the print, and visual acuity of the observer. The standard assumption is viewing 8x10 print at 10-12" viewing distance, but a viewer with LESS THAN 20/20 visual acuity! That is why both DOF and diffraction effects are subjective, and vary from one person to another (and how imperfect their vision happens to be).

The Amount of diffraction is easily quantifiable to a number, but the subjective criteria is whether or not that much diffraction is 'detectible' and 'acceptable' to the individual.
For DOF calculation the CofC size very much depends upon WHICH DOF calculation...before making a recent post on that topic, I looked up the CofC sizes of three different programs chosen at random...0.25mm, 0.30mm, and 0.33mm...which one do you select to use, and which one is representative of YOUR vision and thresshold of 'acceptably in focus'?!
So how big of a Diffraction number will you also find to be acceptable to you?

DREW WILEY · Dec 14, 2022

Going back to use of the adjustable Sinar dial ... Well, I scrubbed off the necessary dotted lines from my Sinar GG anyway. Found them distracting.

Sharktooth · Dec 14, 2022

DREW WILEY said:
Going back to use of the adjustable Sinar dial ... Well, I scrubbed off the necessary dotted lines from my Sinar GG anyway. Found them distracting.

You can still make use of this feature if you still have any lines marked on your screen. All you need is two lines with a know distance between them. They can be anywhere on your screen that you want. You can put a piece of masking tape around the existing tilt calculator knob to put on your own tilt markings. You could also put two vertical lines on the screen for the swing angle calculation. If they're the same distance apart as the horizontal lines, then the knob markings you made would be completely compatible for swing angle.

If your camera has one of those slip rings for depth of field calculation, you could tape over that to put your own markings for tilt or swing.

It's all based on simple high school trigonometry {{{SHUDDER}}}. The tilt angle is = arctan(L/H) where L is the linear focus displacement between the two points on the ground glass, and H is the vertical displacement of the two points on the ground glass. Sinar uses 70mm for the displacement between the lines on the ground glass, so H=70. The slip ring on the tilt calculator knob turns proportionally to the focus displacement, so it's easy to put any scale you want on this.

The real beauty of this approach is that it is all done on the back, and there is no tilting required on the back. Just choose two points on the ground glass and then focus the back at each point. The focus difference between these two points is the L dimension.

Even better, it doesn't matter where the two points are on the ground glass are, as long as you have a calculator to do the arctan(L/H) calculation. This would work well with a grid screen with 1cm squares. You could choose any two points you want for the tilt or swing, and just note the number of squares they are away from each other to find the H dimension.

Since everything is done at the back first, you don't need to be reaching out and fumbling with the front tilt at the same time you're trying to focus with it while tilting.

It's not better or worse than the conventional methods, but it's another option that may be useful to some. A tip-o-the-hat to Sinar for this.

DREW WILEY · Dec 14, 2022

Thanks, but no point in my case. I haven't done any studio-style tabletop photography in the past 20 years. And I don't live in Kansas or anywhere else as flat as a tabletop. Focus and depth of field strategy has to be based on a variety of compositional and esthetic variables, and not just hypothetical regular geometric planes which are rare in nature anyway.

I was kicked out of high school trigonometry anyway. The teacher didn't like my older brother or sister, so decided to refuse me his class too, even though I otherwise had the highest science grades of anyone in that school. He was an eccentric; and every time he turned his back to face the blackboard, it got peppered with spit wads. Almost nobody respected him. One that did, we called an IBM computer on stilts - a kid with long skinny legs who subsequently went to Cal Tech and then got on the ground floor of Hewlett Packard and made millions. But he didn't like paying income taxes, so spent a decade in Federal prison, and afterwards became the most knowledgeable minimum wage security guard in history - at the Tech Museum in Silicon Valley!

Sharktooth · Dec 14, 2022

Tut tut, excuses, excuses. You disappoint me, Drew. I thought you'd be the last person who would wince at a simple challenge just for the hell of it.

DREW WILEY · Dec 14, 2022

No, I didn't cave in. Just waited until the jerk was on leave; and the substitute math teacher was willing to personally tutor me. But I don't play billiards, so what use is trig geometry anyway? But I'm from way back when math grades equated to the quality of slide rule you could afford. I had to use the worn-out wooden school ones. Analytic geometry was a piece of cake, and well worth promptly forgetting too. I have concocted some special darkroom programs based on it; but all I need for that is a basic ten buck math calculator rather than remaining brain cells.

Sharktooth · Dec 14, 2022

I suspect you may be suffering from a later life reemergence of your childhood trigonosis disease, Drew. It's cosed by a nasty parasite found in untaned bellows leather, and the outward sines are a severe blather infection. The good news is that it can be treated with the right formula, but as with any treatment, there is always a small calculated risk. Good Luck!

Sirius Glass · Dec 14, 2022

Sharktooth said:
I suspect you may be suffering from a later life reemergence of your childhood trigonosis disease, Drew. It's cosed by a nasty parasite found in untaned bellows leather, and the outward sines are a severe blather infection. The good news is that it can be treated with the right formula, but as with any treatment, there is always a small calculated risk. Good Luck!

Is this a tangent?

DREW WILEY · Dec 14, 2022

More like a ricochet, it seems.

Sharktooth · Dec 14, 2022

I wouldn't call it a tangent, more like looking at it from a different angle.

Sharktooth · Dec 14, 2022

.... and always keep in mind that old adage "two hypotenuses don't make a right".

Sharktooth · Dec 14, 2022

To be fair, everyone has their own unique perspective. Some may tilt towards a single methodology, while others may swing freely between several. The key is to stay focused on the methodology you're currently using. That being said, you don't need to remain shuttered to the old ways, stay open to new ideas and concepts.

Well, that's enough for today. Sineing off. ..... finally

wiltw · Dec 14, 2022

Drew Wiley said:
But I don't play billiards, so what use is trig geometry anyway?

Funny...photography is the only area in which I have found (on many occasions) the practical applicability of the understanding of trigonometry, and consulting of the trig tables...

calculation of flash position along umbrella shart, and the FL coverage setting to fill a particular diameter umbrella
calculation of human eye visual acuity and the corresponding number of pixels needed for a given mural size and viewing distance

just a couple of examples.

Vaughn · Dec 14, 2022

John Patrick Garriga said:
So does X-ray film have a special affect? I know it's supposed to be high ISO but is there anything else special about it that would come up in regular shooting?

The double sided x-ray film has no anti-halation layer, which can enhance the glow mentioned above. There are some sizes of one-sided x-ray film made.
Double-sided used to photograph my boys -- until then I did not notice how many freckles Calder had...and his clothes were reddish. The film can be handled under a red safelight -- and certain does not react much to red out in the field! Platinum/palladium print

John Patrick Garriga · Dec 15, 2022

Vaughn said:
... and certain does not react much to red out in the field!...

I may only use this rarely in that case. I'd mostly be wanting something that's not as reactive to blue. I want to have my skies darker and this seems like it'd give the opposite effect.

Sirius Glass · Dec 15, 2022

John Patrick Garriga said:
I may only use this rarely in that case. I'd mostly be wanting something that's not as reactive to blue. I want to have my skies darker and this seems like it'd give the opposite effect.

In order of darkening skies: Yellow, Orange, Red 23, Red 25 filters. The last can make skies almost black. Polarizers depend on the relative angle of the sun.

Donald Qualls · Dec 15, 2022

Yeah, blue is the first thing silver halides are sensitive to (along with UV). Even simple homemade emulsions (like collodion wet plate) are sensitive almost exclusively in blue (that's why those Civil War photos have white skies). There are films with "extended red sensitivity" that can lighten reds and thus allow reduced exposure to darken greens and blues (Catlabs 320 is apparently one such). Films labeled as "infrared" might do this.

You can also put a "minus blue" filter on the lens -- this will look orange-ish, and will reduce blue light but have minimal effect on green and red. A red filter will do more of this.l

First Large Format (Ignorance and Expense)

Attachments

Privacy & Transparency

Privacy & Transparency