Bellows extension cheatsheet for SA 90 XL, SS 150 XL, 300M?

[pchaplo]

Wondering if anyone has created spreadsheets for quick bellows extension guide. I shoot 4x5 using Schneider Super-Angulon 90/5.6 XL, Super-Symmar 150/5.6 XL, and Nikkor 300M/9.

I usually do landscapes but now I want to shoot some details and textures at close range. I will probably start with the 150 XL and 300M so those are my priority.

Edit: I’m thinking I will use the 150mm for starters on my 4x5. If you use an example of a closeup, please use 150mm

[Bob Salomon]

Why? It is pretty easy to just look at the gg. And what image ratios would you want it for?

[Dan Fromm]

Key magic formulas:

extension = focal length *(magnification + 1)

Extension is measured from the film plane to the lens' rear node. For most LF lenses the rear node is close to the diaphragm.

Front node to subject distance = focal length *(magnification + 1)/magnification

For most LF lenses the front node is close to the diaphragm.

effective f/ number= f/ number set * (magnification + 1)

You're going to need 600 mm extension to shoot a 300 mm lens at 1:1. Front node to subject distance will also be 600 mm. There are some subjects for which that much working distance is helpful, but in general you'd be better off using a shorter lens at 1:1.

[pchaplo]

Thanks Dan,

Good point. I will start with my 150mm.

Key magic formulas:

extension = focal length *(magnification + 1)

Extension is measured from the film plane to the lens' rear node. For most LF lenses the rear node is close to the diaphragm.

Front node to subject distance = focal length *(magnification + 1)/magnification

For most LF lenses the front node is close to the diaphragm.

effective f/ number= f/ number set * (magnification + 1)

You're going to need 600 mm extension to shoot a 300 mm lens at 1:1. Front node to subject distance will also be 600 mm. There are some subjects for which that much working distance is helpful, but in general you'd be better off using a shorter lens at 1:1.

[Drew Wiley]

Today I used a little gadget from Calumet. It's a little plastic crosshair card you place in the scene, then you measure the width of it on your groundglass using a special plastic ruler marked in f-stop factors. Really portable and works for all lenses. Maybe someone else is making something like this now that Calumet is gone.

[MikeMGB]

Today I used a little gadget from Calumet. It's a little plastic crosshair card you place in the scene, then you measure the width of it on your groundglass using a special plastic ruler marked in f-stop factors. Really portable and works for all lenses. Maybe someone else is making something like this now that Calumet is gone.

I have the same, mine is actually printed on paper and laminated. It's at work right now but if I happen to be reminded on this thread on Monday I could scan it and post pdf's somewhere for people to download.

[biedron]

Today I used a little gadget from Calumet. It's a little plastic crosshair card you place in the scene, then you measure the width of it on your groundglass using a special plastic ruler marked in f-stop factors. Really portable and works for all lenses. Maybe someone else is making something like this now that Calumet is gone.

You can make your own using the download at http://www.salzgeber.at/disc/

Bob

[Doremus Scudder]

I don't want to do any calculating in the field. The exposure disc is a good tool, but having to place it in the scene is a disadvantage, especially in the field for found and delicate foliage shots, etc. I prefer just to consult a chart.

I've got my exposure record book with me in the field and that has charts for bellows extensions for all the lenses I commonly carry (plus reciprocity adjustments, filter factors etc., etc.) I only have to measure and look up my factor. I'm attaching the charts here for those that may find them helpful.

There's one chart in mm and one in inches so you can measure how you like. Feel free to copy, modify, whatever to suit your needs.

Best,

Doremus

[Tin Can]

Very nice Doremus and I mean that 2 ways.

Beautiful chart well sized to be usable on a phone or printed. Nicely done!

A wonderful gift and accommodation for metric or imperial practitioners. Nice!

Thank you!

[pchaplo]

Thanks Doremus for sharing the chart that you developed. I appreciate your kind generosity, and this tool will help many others for a long time!