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I think we should ban Donald Trump from this forum. Just because everyone else is doing it...

Seems like a waste of a good India Pale Ale...

I second this.

I've found the main culprit in getting glass spotlessly clean isn't the cleaner used, it's the cleaning cloth.

Paypal is the norm, but really, it's up to the buyer and seller to work it out however they are comfortable.

Helpful hint: Use a second piece of glass to do the grinding, and you get two pieces of ground glass for the same time and effort.

Yes it is. You shoot some hokey bokey and you turn yourself around.

That's what it's all about.

The B&J is a fairly heavy camera, at the far end of what most people would consider a "field camera". Trying to save weight on the lens is wandering into the area of diminishing returns, like...

For some of the more knowledgeable users, the shutter is as important as the lens...

That's the usual method for bellows with very worn corners. Pretty obvious advice, but:

Stretch out the bellows as much as you dare before taping.

Use a flexible fabric paint (available at...

I'm always right, and I never lie! :rolleyes::rolleyes::rolleyes:

Best to assemble the lens in its new shutter and determine the f/stops by measuring. The new Alphax may not close down at the same linear rate as the old shutter.

Primitive Photography: A Guide to Making Cameras, Lenses, and Calotypes, by Alan Greene, has a 58-page chapter that does a decent job with the basics.

Well, "Tessars types, Commercial Ektars, Dagors, some Artars" are all pretty flat field, so it's not field curvature. Maybe the camera was out-of-kilter, and needed a degree or two of front tilt to...

The more I eat and the older I get, the larger the format of my body seems to be.

Not yet sure about the lens, though...

The first thing you need to do is build an optical bench to test the various configurations. Otherwise, you won't know whether what you're building works until after it's built. Just a few mounts...

Unless you're using Petzvals or meniscus lenses, I doubt it was field curvature. Regardless, front tilt won't remove field curvature. No movement will. Could be focus shift from stopping down, but...

But think how much better large format photography looks on a cell phone!

That was my next guess.

Not much to go on...

90mm, f/22?

A second for Hugo's suggestion of a Dagor; nice for portraits wide open and sharp with lots of movements closed down. And you can probably find a newer one in a decent shutter.

If it weren't for...

That makes sense! Thanks!

But is chromatic aberration a geometric effect? :confused:

That makes sense. But the diffraction limits calculators I've seen go by f/stops, not actual aperture size. And of course, f/stop dimensions change with focal length, as that's the "f" in "f/stop".

In our case, that would be an opening in the photon-wave-amplitude size, something well below f/64 for our lenses.

One thing I don't understand about diffraction is why it is affected by focal...

Agreed, Drew, but which other aberrations are ever corrected to perfection, not just reduced or avoided?

Diffraction can be corrected by opening up the aperture. Just like you can correct spherical aberration or curved field by closing down the aperture.

But one can also correct spherical aberration...

Why isn't diffraction considered an optical aberration? It's missing from the conventional list of aberrations.

Late night pondering... :confused:

Jim's post reminds me of a little trick I learned from ancient markings on a couple of my old shutters: put little paint/pencil marks on the aperture scale at 1 inch and 1 centimeter. It makes the...

For large format, this is key. If you're contact printing, (no enlargement of the negative), forget diffraction. It will barely show up at f/256.



Nitpicking, but isn't 1:1 and f/16 nominal...

At my age, I'm wondering whether a balsa wood tripod would work...

The Ries tripods are made from Hard Maple/Rock Maple/Sugar Maple (all the same), though the company has recently been offering other woods on "custom" tripods.

It was all a hoax! Fake certificates are the Reptilians' way of controlling our minds! Spots on your negatives are caused by having sex with demons in your dreams! Watch You-Tube for the real...

Yup, I got it too.

Most strobes have variable output. You can also use films of different ISOs, if you aren't committed to one film in particular. ND filters on the lens, or over the strobes, (those on the strobes...

Modern coated Dagors are always nice, reasonably light, and fairly bright.

If I was talking about coma, I would have said coma, as I did when talking about coma earlier. I didn't post a link.



Yes, and you can also increase spherical aberration by altering the...

As you change the position of the stop, you change where rays coming from off the optical axis though the aperture strike the lens. In a lens with significant spherical aberration (like a meniscus),...

I worked with one in a studio many times without. No problem, even wide open. If you're working outside in the daytime, yep, you'll need an ND filter or a shutter, (do a search for "Galli shutter",...

Just a note that aperture position is one of the "design freedoms". There's some choice involved because different positions are the "sweet spot" for minimizing different aberrations. The sweet...

If you're doing still lifes, the Tessar may well cover at close distance.