Schneider Super-Symmar 80/4.5 XL - NOT sharp???

Your two dealers are about four years behind the times. As Bruce indicates, there were some problems with some of the lenses in the first production run of the 80mm SS XLs. That started a lot of discussion, some of it here (which you should be able to find if you search), about the lens not being sharp. Schneider quickly fixed whatever the problem was and as far as I know all 80mm SS XLs since that first run have been fine. I've owned mine for about two years and it's a great lens, tack sharp at any aperture I use (I don't use it at f4.5 except to focus).

Excellent exchanges - thanks to the group for your thoughts.
I'll spend tonight digesting all of this info.

Is there a standard test pattern/chart that is recommended for running my personal test of the lens?

The Jobo Expert 3006 drum arrived today so I can be up and testing shortly.

Thanks again to all who contributed!
Jack

My suggestion for a test chart: a brick wall. This works well for a qualitative test -- why do you need to know line pairs per mm resolution? Just get your camera perpendicular to the wall (levels and ground glass grid lines or edges compared to the bricks are helpful) and take photos at the apertures that you might use the lens. Apply the largest front rise that you might ever use (or the equivalent shift, if more convenient). Compare the different apertures, and the edges against center, to see whether the sharpness meets your needs / wants. You should see the coverage increase with decreasing aperture (larger f-number). Be sure to make your judgements at the largest enlargement that you will use, or with equivalent loupe power.

i tested my 80xl for hand held use and made 2 shots 250 sec on f8 and 250 on f11, this lens is soft at f8, and you don't have to be a lens expert to see it, oh, and yes i have a new version.

but at f11 or > this lens is amazing, i woudn't give it back if i were you, i am making 54x70" mural prints of a series of pictures made with this lens and they are exceptional.

I'm not sure if most people are aware that the wider the lens, the deeper the depth of field, but the smaller the depth of focus, i.e., the focus at the film plane. So any evaluations of the lens wide open would have to include how accurate the relationship of the ground glass is to the film plane. And just as the lens gains depth of field when stopped down, the depth of focus also is increased. With "normal" or longer lenses this generally isn't a problem since the depth of field (what's in front of the lens) is less, but the depth of focus (the focus at the film plane) is greater. I'd buy one of the problem lenses in a heart beat since the issue probably isn't the lens but the tolerances of the camera and the operator.

Kind Regards,

MW

Mark, it is a common belief that depth of focus is smaller for shorter focal length lenses, but the equations don't agree with this. For distant subjects, the equation simplifies to depth of focus = 2 C N, where C is the diameter of the circle of confusion and N is the aperture (f-number) -- the focal length doesn't appear in the equation. Maybe the idea comes about because smaller formats have smaller depth of focus, because they have smaller circles of confusion on the film, because greater enlargements are needed, and this gets associated with the shorter lenses used on smaller formats.

Michael Briggs wrote "My suggestion for a test chart: a brick wall. This works well for a qualitative test -- why do you need to know line pairs per mm resolution? "

Michael, a brick wall or anything else with a regular pattern will do fine for a go/no go test if the pattern's spatial frequency matches that of the finest detail that will have to be resolved when a "real" picture is taken. The advantage of test targets that have more than one spatial frequency is that one of the frequencies on the chart will probably be close to what has to be captured. This is why the test shots on, for example, Klaus Schmidt's macro lens site are not particularly informative.

Cheers,

Dan, the brick wall test works well as a qualitative test -- give it a try. The key is that the "test chart" has uniform detail over the entire subject area, so you can see how the sharpness of the lens varies over the film area. You won't get a quantitative measure of resolution. It isn't necessary that the brick size match a spatial frequency of interest -- you can look at how sharp the edges are, and how details on the bricks are rendered. Of course, the farther the you get from the brick wall, the finer the details will be. It's only a qualitative test. One advantage is that the subject is distant, similar to the subjects the lens will usually be used for.