First Large Format (Ignorance and Expense)

Vaughn

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Have you tried a Dark Red filter coupled with a Polarizing filter yet to get black skies?

Glass filters behind the lens can cause focus shift, so focusing needs to be done with filters in place...not so with filters on the front of the lens. Gel filters, I believe, do not cause focus shift when used on the back of the lens....but I will need the back-up of more technical minds here for confirmation.
 

btaylor

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“Cheapo calipers are a recipe for trouble.”

Not when you’re trying to figure out lens cap sizes and filter threads. We’re not building a space shuttle here.
 

btaylor

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Vaughn said:
Gel filters, I believe, do not cause focus shift when used on the back of the lens....but I will need the back-up of more technical minds here for confirmation.
Click to expand...
Rear gel filter holders on large cinema zooms are not uncommon. A clear gel was not needed if you were not using a rear gel. Not the case with the lenses using rear mounted glass filters, a clear filter was needed to prevent focus shift.
 

Vaughn

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Thanks! My information fell into the category of: Things I have heard forever, but have never heard 'proven'.

And I like the idea of a clear (ie, UV filter) on the back of lens for composition and focusing, then replacing with the needed filter. Not that I use rear filters, just neat to hear the solution. Using an f11 lens with a red filter under the redwoods could be tough!
 

DREW WILEY

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btaylor - speak for yourself. I've seen cheapos missing a millimeter. Besides, not many people know how to correctly use calipers for internal thread measurements. It's not like determining a lens cap size. But yeah, as a former Starrett dealer, I have my scruples. I'm not a Harbor Shipwreck type.

Stacking red and pola filters? That's six air/glass interfaces plus the polarizing sheet - not the best recipe for critical sharpness. But lots of people do it; not to my taste however - skies start looking fake.

Few lenses are designed for rear filters - potentially even more image-degrading. Gels per se are prone to grime build-up, fingerprints, creases, scratching, and certainly aren't cheap anymore. Old ones might be partially faded. I never use gels except in the lab/studio.
 

wiltw

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RalphLambrecht said:
The further the bellows are drawn out, more exposure is required
Click to expand...

Expressed differently, as we approach 'macro' magnifications on film, we start to need more exposure because the image circle is increasingly large...fewer photons are striking the same area of emulsion, so more exposure is necessary.

The bellows is extended farther at macro scales, so exposure adjustment is often (for large format) expressed as amount of bellows extension. But it can also be determined by image size on groundglass, compared to life size of subject.

If we are at scales smaller than 1:10, exposure increases is small (1/3EV or less) and at 1:5 scale we need +1/2EV
 

Alan Edward Klein

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...and I grew up in The Bronx. Loads of aborigines there too. No Indians, but we did have Ft. Apache. I wouldn't carry a camera around there for fear of getting mugged.
 

Alan Edward Klein

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Try to get the size filter for the lens with the largest filter required. Then use step-up ring adapters on the front of each of the smaller lenses. That way you only need one set of filters. Just select the right sizes. https://www.bhphotovideo.com/c/buy/step-up-rings/ci/23475

I wouldn't use a back filter because dirt on them will show more easily on the film because it is closer to it.

Buy a new filter with coatings to avoid glare in the sun. Thin, to avoid possible vignetting especially if using multiple filters. Or buy a used filter that's clean. Why screw around making your own and messing up the great optics of a Schneider lens?
 

grat

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btaylor said:
“Cheapo calipers are a recipe for trouble.”

Not when you’re trying to figure out lens cap sizes and filter threads. We’re not building a space shuttle here.
Click to expand...

Gotta be honest, I wouldn't buy the $10 calipers from Harbor Freight either-- not because of a bias against HF, but because their $10 calipers, while digital, are cheap. 0.2mm is a terrible level of accuracy, and there's no depth gauge. It's also plastic, and it lacks a thumbwheel.

Now, the $20 set sitting right next to that.... That's stainless, has the wheel, is accurate down to 0.03mm, and comes with a case.

The set I actually own ($29!! from Amazon), from a brand I've never heard of, claims accuracy down to 0.01mm, and accuracy/repeatability out to multiple decimal points.
 

Donald Qualls

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I have one of the $20 Harbor Freight ones, and it's fine. I've also got (somewhere, probably in a bin in the shed) one of their older, no-battery mechanical dial calipers (same reading precision, but without the easy jump from inch to metric) that in some ways I prefer; cost about the same, as I recall. Honestly, though, any millimeter scale that reads in single millimeters will be enough for sizing filter threads and such.
 

Sirius Glass

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I have a Harbor Freight $10 mechanical calipers and it is accurate and has good repeatability.
 

grat

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I use mine with my 3D printer-- primarily to make sure it's calibrated correctly, but sometimes when modeling parts as well. So a bit of accuracy is desirable.
 
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John Patrick Garriga

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Alan Edward Klein said:
...Why screw around making your own and messing up the great optics of a Schneider lens?
Click to expand...
Firstly, sorry I haven't been active the last few days. Been a bit busy.
I was talking about making my own lens mount, really. May have miscommunicated that. If I did talk about making a lens filter a while back I think I meant making a plate filter like you'd fit on the front of a lens, not a permanent filter to go in front of my lens.
 
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John Patrick Garriga

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Vaughn said:
Have you tried a Dark Red filter coupled with a Polarizing filter yet to get black skies?…
Click to expand...
I have not. I always thought that polarizing filters just made EVERYTHING darker so you could get a longer exposure, get smooth water and things like that. The skies would be darkened equally with the rest of the image. But I’m guessing that must be incorrect.
 
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John Patrick Garriga

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ALSO, Merry Christmas everyone!

I’ll have to invest in a good caliper sooner or later for dealing with filters.
 

Vaughn

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Polarizing filters filter out light coming from one direction -- one can rotate the filter to choose which direction to filter out. Classic example is reducing the light that is reflecting off a surface (water or glass) towards the camera from that direction, allowing one to see into the water or thru the glass.

So one turns the polarizer until the sky darkens -- which darkens the sky proportionally more than the landscape which is lit amply by light reflecting towards the camera from directions other than the polarizer is filtering. I tried it a couple times, but never printed the negatives. Below is as dark as I usually might go (8x10 platinum/palladium print, YNP)

One of the issues with polarizers is that they can accidentally eliminate highlights that liven up an image.
 

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Doremus Scudder

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MTGseattle

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The OP is not new to photography, just new to large format right? Filters will do the same thing to a given film stock regardless of film size (I'm sure there's a small caveat here, but this thread seems to have gotten into the weeds a bit already).
I wouldn't worry about getting the black sky you love on your first few sheets. You can certainly give it a shot, but you have the camera itself and its inherent movements to get used to. you may forget to lock one knob down and blow the focus on an otherwise properly exposed and composed image. The paper negative option is a valid cost saving option, but it's not an apples to apples data gathering source. You may have people suggest Xray film too for which I would make the exact same comment.
I guess what I'm trying to say is don't heap every variable onto your first outing with the new camera (Bellows extension factor, filter factor/s, etc). get a feel for the thing and add the minutia as you see fit.
 

Doremus Scudder

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If you confuse a polarizing filter for a neutral density filter, you need to brush up on how filters work. Hence my providing links to a few sources.

Best,

Doremus
 
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John Patrick Garriga

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MTGseattle said:
The OP is not new to photography, just new to large format right? ...
Click to expand...

That's right. I've been shooting day in and day out for about two years now. Not a lot compared to the lifetimes of experience on this forum but I like to think I know my way around a camera. Somehow I just never got around to needing to use a filter.
Anyways, it's all "gotten into the weeds" because I just wanted to learn as much about the camera, and shooting film in general, while waiting on everything to arrive. I'd like to have as few technical goofs as possible if I can.
 

Vaughn

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I have used a red filter as a neutral density filter to allow me to use a slower shutter speed. In this scene, there really was not much color to be affected by the filter. This river appears from a glacier about 50 yards upstream and was milky not quite white...no blue and moving extremely fast. At f64 at 4 seconds (4x5, 150mm lens, Super XX).

A re-photographed loose 16x20 silver gelatin print. The negative did not match my expectations -- I was going for the water to mirror the forms of the rocks. But I did not get the definition in the shape of the water as I hoped. Going with the direction of the negative, I worked it into an active fog instead. Amazing place to work. I heard/felt the clunks of rocks and/or chunks of ice being carried by me in the river as they hit the river bottom. I really like those (relatively) tiny chunks of ice in the foreground.

Pretty exciting place -- a place where one could easily die. Watched some rocks fall and speed right over a rock I had the 4x5 set up on a few minutes before. Areas around receding glaciers are unstable, but very photogenic. I finished the image I was working on and retreated myself. And yes, I had gone past the sign that said do not go pass this sign.
 

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Alan Edward Klein

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John Patrick Garriga said:
ALSO, Merry Christmas everyone!

I’ll have to invest in a good caliper sooner or later for dealing with filters.
Click to expand...

The link below shows lenses used for 4x5 and their filter sizes. The other links to info about large format photography and getting started. You might consider also joining Large Format Photography. They focus on that type of equipment. I belong to both it and Photrio as they both focus on film.

Main reference page: https://www.largeformatphotography.info/
Filters: https://www.largeformatphotography.info/filters.html
4x5 Lenses specs showing filter size required: https://www.largeformatphotography.info/lenses/LF4x5in.html
 

MTGseattle

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@Doremus Scudder Ah. I see which post you were referencing now. Yes, that would be an issue.

For the OP, I have a General brand caliper. It's the stainless version with the lcd display and can do three types of dimensions. The current one seems to cost $90 or so. I've had mine quite a while, and feel like I would have balked at 90 dollars. I think it may have been around $40 when I got it. I have 3 EL-Nikkor enlarging lenses that are supposed to be 39mm. My caliper measured them all differently. I need to get my hands on some accurately machined spacer blocks or something and see if the caliper is wacky I guess.
 

GregY

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JPG, I'm not sure why you'd need calipers. The typical range of LF lenses, by Nikon, Fuji, Rodenstock, Schneider, Kodak, Dagor et al.... all have known published filter & cap sizes....easily found on the web. The same goes for the size of the shutter they require. What am I missing re your question?
 
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