[clackers]

. I also am going to try a new DFA50 macro as soon as it arrives. I am pretty happy with my results so far but if they can be improved I will be even happier!

Yep, shoot it at f8, not f16.

It's very sharp, BTW - I own one.

[sibyrnes]

Well, I just got my new DFA 50 Macro. Here is a slide shot at f8:

[Medex]

Well, I just got my new DFA 50 Macro. Here is a slide shot at f8:

this lens has best specs at f4.
Pentax D FA 50mm f/2.8 macro - Review / Test Report - Analysis

But at that aperture the DOF is very narrow (0,288 cm at 20 cm focus distance), you shuld be sure that your slide is almost absolutely flat.

[sibyrnes]

this lens has best specs at f4.
Pentax D FA 50mm f/2.8 macro - Review / Test Report - Analysis

But at that aperture the DOF is very narrow (0,288 cm at 20 cm focus distance), you shuld be sure that your slide is almost absolutely flat.

Yeah, that's the problem - 25 year old slides are "almost" absolutely flat.

[Na Horuk]

Well, I just got my new DFA 50 Macro. Here is a slide shot at f8:

I think f8 is good. Even if f4 has more resolution, you are limited by the resolution of the slide itself, and that resolution is most likely lower than DFA 50mm on K-1. And I don't think the difference between f4 and f8 is that big, on that lens. Probably meaningless once you factor in the slide resolution (unless one of those special super high resolution films was used)
The results look good, the peak of that mountain is sharp and detailed.

[Bob 256]

I have a Nikon Coolscan 4000 which scans slides or negatives at 4000dpi. It's limited the 35mm sized format. Typically I would use this scanner for anything I wanted to convert to digital format because it has some advantages over using a K-1 (the K-1 has some advantages also - read on). The Coolscan uses four LEDs for scanning - the typical red, green, and blue, and a fourth infrared which detects dust, scratches, etc. That fourth light source allows corrections to be made in the file generation process, filling in defects (and it does a pretty fair job). The Nikon also has processing called ROC (restoration of color). I've used it on some faded Anscochrome slides and the results can be amazing. Note that the latter feature is strictly in software that comes with the Nikon while the cleanup work takes place in hardware & software. The downside is that the scanner is slooooooow. It can take several minutes to scan a single slide if more features are implemented (like scratch removal and multi sample scanning), but it does a great job. Output is 8 or 14 bit.

In the past, I have contemplated using a digital camera to speed up the process. I have an old 35mm dichroic color head that I plan to use for illumination. It provides a diffuse source that can be color trimmed for each primary color. Diffuse is the key word here since any focused light source will emphasize scratches and surface defects in the film (so if you're going to use a source for the K-1, consider a piece of frosted or opal glass, uniformly illuminated from behind, and separated some distance from the film to be scanned so its surface defects are out of focus. When I hear "projector", I think of one of these cheap gizmos that projects the slide on a transparent screen and you shoot it from the opposite side - Nooooooooooo! Very inferior to direct imaging - all the screen defects show up. Just use a diffuse backlight and good lens. As suggested, an enlarger lens is good and has high resolution. Since you're shooting 1:1, the orientation doesn't matter (it's not fully optimum either way). To get absolutely the highest resolution, you need a high quality 1:1 lens which is designed for that conjugate ratio (and I have no suggestions available - a good enlarger lens (stopped down) will do the job pretty well). Use that with a bellows or specific extension tube to get 1:1 and you're there with the K-1. How much detail is in a slide depends on several things. First, how good was the original lens used to capture the slide. Second, what film was used (Kodachrome 25 was tops and could capture upwards of 100lpmm or more). Then there's the question of focus, how steady the camera was, aperture used, and a few other things. All in all, I've seen details that exceed the 4000 dpi capability of my Nikon (using a loop to look at the original), though that's not at all typical of an average image.

So it boils down to the fact that the K-1 may indeed capture details better than a 4000 dpi scanner since it theoretically has around 5000 sensors across the film width (about an inch) and it would be much faster than using a typical line type scanner (like the Nikon), but I would for go all the rental equipment and just use the K-1 with a good lens and light stage for the slide. You won't get any automatic dust or scratch removal though, and you'll still end up post-processing some or all slides (the latter of which is true for most any scanning).

On the other hand, you might consider renting a scanner similar to the Nikon (don't forget the software) which would also do a great job though much more slowly (some used models are available on ebay).

In summary: Speed - the K-1 or equivalent (with a "cheap" light source & "suitable" lens
Automatic dust/scratch reduction & color correction for aged slides - The Nikon or equivalent

Wordy but just my take.