Any point in upgrading a slide projector lens ?

<p>I got a Kodak Carousel 4600 projector, for free, from my work. It all seems to work well enough. I have read, here, and in other web places, that the stock lens is not that great. Since it would cost quite a few bucks to get a Leica projector with the well reviewed 90mm lens, that's out of the picture. However, I have found there are other lenses I could use. Which ones are good ? It's just for personal veiwing, not for some business slide show.</p>

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<p>The one you have is designed and great for a house.... Others are fore longer rooms. you got ir why worry about the lens as the bulb won't be around much longer.</p>

<p>John, I do recall that some lenses exhibited more or less barrel distortion. Depending on how finicky your audience and what you're projecting, that might be important. It's been too long ago to recall which lenses were better. I truly liked my Rollei projectors for running cool and having great optics, but the Kodak's were no slouches.</p>

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<p>It's just for personal veiwing</p>

 

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<p>Well is there any reason you don't just set it up and judge for yourself whether the projection quality is good enough? Seems like a question that might best be asked if you know there's an issue and understand what you'd like less or more of?</p>

I don't know about your's but some Kodak projectors offered a choice of focal lengths for different projector to screen distances. What you have now may not be suitable for your situation.

<p>The most important factor is the lens speed. The standard Kodak lenses I have are f4; I found some f2.8 lenses (Golden Navitar for curved field, Schneider for flat field), and the difference in image brightness is enormous. Those lenses are also considerably sharper with better contrast. They can be hard to find, but if you can, they often come at a quite reasonable price, and I think the extra investment is very well worth it.</p>

<p>My f2.8 Schneiders gives a brighter and sharper image over the standard Kodak offering.</p>

<p>David,</p>

<p>I think the question you asked, was answered FOR me, just a few posts down.</p>

<p>"I found some f2.8 lenses (Golden Navitar for curved field, Schneider for flat field), and the difference in image brightness is enormous. Those lenses are also considerably sharper with better contrast."</p>

<p>I would like to see the sharpness of the slides to show on the screen, not just on the lightbox. I did a quick view at my parents, since they hadn't been to the spot my family went, and I just didn't get any wow factor.</p>

 

<p>Ted,</p>

<p>"(Golden Navitar for curved field, Schneider for flat field)"</p>

<p>What are the differences and when do you need one over the other ?</p>

<p>Btw, I see my lens is a 100mm f2.8.</p>

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<p>John-<br>

I used to shoot almost exclusively Kodachrome. When those slides are mounted in the cardboard mounts, they have a small curvature (easily seen if you look at the reflection of a light off the surface). When in the projector under illumination, the slide heats up due to the lamp, and the slide actually "pops" after a second or two so that it has a well-defined curvature. (Your projector may even have a vent to use heat from the lamp to pre-heat slides before they get to the viewing slot.) A curved-field lens is designed so that it images that curved surface onto a flat screen; that's the way you could get reasonable center-to-edge sharpness without having to use a glass slide mount (not quite as sharp, but usually pretty good). A glass slide carrier holds the slide perfectly flat, so then you need a flat-field lens.<br>

Now, all my slides from the 70's up until about 2000 or shortly thereafter work this way, so I use the curved-field lens when looking at older slides. In the past few years, though, I have been shooting mostly Provia for 35-mm projection, and for some reason those slides seem to stay flat in either cardboard or plastic mounts, so I had to find a flat-field lens to view those. I have found recent Provia (or Velvia) slides to be unviewable with a curved-field lens.<br>

I am actually quite curious if anyone can tell me how the current Ektachrome films behave in this regard. I've been very happy with Ektachrome I've been shooting in 120, but I haven't tried it in 35 mm. I would prefer if it had the curvature - I think it usually gives a slightly sharper projected image.</p>

<p>I have about 10 boxes of Extachrome slides, from two different photo houses. I'll take a look at them. Just how obvious is the curve, before heating ? Would it be better to run some through my projector and pull them out warm to check ?</p>

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<p>The curvature is observable, but it is small so it's hard for me to advise. Another strategy is: if one of the slides is lousy and thus disposable, take it out of its mount and lay it on a flat surface. Does it lie dead flat, or have enough curl in it so it sits on its edges ? I did this test with my recent Provia film and found it lies perfectly flat. So, when projecting the flat film with a curved-field lens, the corners were *really* out of focus.</p>

<p>Although somewhat dimmer, the f/4 lens from Kodak has obviously more depth of field and can therefore cardmount mounts/glass mounts do not matter. At least that has been my experience.<br>

Home viewing on a projected screen has not had competition in the past, however since large screen 1080p plazma displays are becoming quite common, their brightness competes with the f/4 choice though.</p>