Leitz Pradovit 153 DU/Colorplan 2.5/90 Focus problem

[manoj_rajappan]

I am new to slide projector stuff. I bought an old Leitz Pradovit 153 DU/Colorplan 2.5/90. Auto focus works ok. The sharp focus area is at the center. If I move the lens forward(by manual focus override) left side gets focused sharp. If I move the lens backward then the right side gets sharp focus. In other words the focus moves from left to center to right as the lens moves back and front.

Let me know if anyone knows this problem. Or is it the way old projectors work ???

[john_collier5]

Is your screen parallel to the slide? It sounds as though the

screen is not. Line evrything up anf try it again.

 

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Cheers,

[Robin Smith]

Your focussing issues remind me of my older Agfa projector (same basic

design as the 153s) it did all this kind of weird stuff for no good

reason too.

 

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If you want real sharp imaging over the whole screen simultaneously

then you need to glass mount the slide. I don't glass mount 35mm

slides.

 

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Personally I do not think the 153 are satisfactory projectors - most

of these issues such as weird focussing patterns are due to poor

heating or cooling of the slide in the gate, the 153s are not alone -

in my experience very few modern projectors do a good job of this -

exceptions are Leica Pradovit Color 250s, C or CA 1500, C/CA2500,

CA2502, P2000, P2002 etc. These are the Rolls Royces of projector and

do a excellent (but even they are not perfect) job.

 

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If try and project a glass mounted slide it should be sharp all over -

if it is not then your projector lens or slide gate are at fault. If

it is sharp, then it is a cooling/slide flatness issue and the only

solution is to get one of the above mentioned projectors. This is my

experience from exhaustive study and frustration at the same problems

back in the early eighties. I don't think anything significant has

changed since then, but I am happy to be corrected.

[jay_.]

I have a Leica Pradovit RT-s with 90 Super-Colorplan-PRO. I

encounter the same issues of uneven sharpness.

[auguste_lacroix1]

I have exactly the problem described with a Leica P255 equipped with

a Colorplan 90mm. Either the left side is sharp, or the middle or the

right (I can change that by manual focusing) but it is impossible to

get all image sharp. The problem is very important and my projector

is almost unusable now. This is the current problem. Before (I did

nothing to explain this), the problem was a sharpness problem from

the top to the bottom: Any vertical portion of the image could be

made sharp by making the other portions fuzzy ! Maybe the complete

slide frames can move too easily due to heat, air flow and this

explains the problem. I am continuing the Problem determination. Same

problem with another lens, same problem with any skide. My projector

is perfectly horizontally and vertically parallel to the wall.

[michael_carlo]

Put your slides into glass mounts. The problem will disappear.

[eliot]

This is a problem with all slide projectors with only a handful of

exceptions. It is due to a slight curvature of the slide surface, so

that the center is in a different plane as the edges. Slide

projector lens are almost always flat field lenses. There are two

solutions, one suggested above is to mount the slides in glass

holders, which is unfortunately not very convenient. There are also

curved field projector lenses that can take into account the lack of

flatness of the slide surface. i don't know much about these lenses

or even if Leica makes one.