step wedge

[philip_sweeney]

On the BTZS forum phil mentioned a longer scale step wedge may be

available which goes to 4.0 with 27 steps. Does anyone know where

these may be available?

[john_cook1]

How about their on-line store?

 

http://www.viewcamerastore.com/catalog/default.php

 

John

[don__]

My question is, why would you need a 4.0 density step tablet?

 

Don Bryant

[philip_sweeney]

For the BTZS tests I have been doing the 4 minute curve is hardly long enough. So I have been doing a 6th negative 4 stops over. This gives me 6 more increments on the 4 minute curve. Of course you cannot add the extra data with the BTZS software, this has to be done on hand drawn curves. (I have not bought the software for this reason. I think it is a serious limitation.) Phil has mentioned a couple of work arounds. One includes the step wedge I mention and one would omit a few steps in the middle of the curve.

 

I use a photoflood for my exposures not an enlarger lamp.

 

No the view camera store does not have any.

[pete_caluori]

Greetings,

 

You can get all sorts of step wedges from Stouffer graphics, both transmission as well as reflective. http://www.stouffer.net/

 

Regards, Pete

[Bill C]

philip, I don't know exactly what you're doing in your tests (I've never read BTZS), but if a transmission step wedge is what you want, Pete's link will do. The Stouffer number T4110 transmission step wedge says it has 41 steps in 0.10 density increments, going to a max density of 4.05.

 

FWIW, if you have a couple of the "normal" 21-step transmission wedges, you could lay a sheet of neutral density filter over one of them. Density values can be simply added, so, for example, laying a sheet of 0.90 ND over the step wedge will cause every original density value to increase by 0.90. (Note: the effect is the same if you put the ND filter over your lens.)

 

If you are actually photographing reflective targets (I suspect you may be since you're shooting som many negatives; ie, six), I doubt that you will find such a target. For various reasons, reflective targets do not typically get darker than roughly 2.0 reflection density. FWIW, you could also use a ND filter in a similar way as above. However, for a reflective target, do NOT lay the ND over the target, put it over the camera lens. So, for example, if you put a 0.90 ND filter over the lens, every original density value on the step wedge will increase by 0.90.