Minolta Dimage Scan Elite 5400 mounting direction

[Pau]

I've scanned hundreds of slides with a Nikon Super Coolscan 4000ED and an important issue is that the slides never end completely flat (in fact usually I dismounted them from the frame an put them in a negative holder to partially correct it)

Could some field curvature have been bundled in the lens design?

[enricosavazzi]

I've scanned hundreds of slides with a Nikon Super Coolscan 4000ED and an important issue is that the slides never end completely flat (in fact usually I dismounted them from the frame an put them in a negative holder to partially correct it)

Could some field curvature have been bundled in the lens design?

It is certainly possible. I seem to remember something being discussed to this effect.

[Vector1968]

Enoplometopus, nice work!

[Enoplometopus]

@Vector: Thanks :-)

[Enoplometopus]

@Rik: I uploaded the last two picture crops again, cropped in Capture One with the size of 1024 pixel. Does it work this way?

[Lou Jost]

Those look really nice!

[rjlittlefield]

@Rik: I uploaded the last two picture crops again, cropped in Capture One with the size of 1024 pixel. Does it work this way?

Yes, this looks perfect. I overlaid the new crops onto the whole-frame image at http://www.photomacrography.net/forum/u ... 14C2_1.jpg, adjusted the scale until the image content matched as well as I could, then measured pixel counts. The new crops as displayed are 1024 pixels wide, and when I measured and ran the calculations as before, I was shocked to get 1024.634. Considering that the measurements are really only good to about 1 part in 100, that's, um, "well within measurement error". Nice job!

--Rik

[RobertOToole]

I've scanned hundreds of slides with a Nikon Super Coolscan 4000ED and an important issue is that the slides never end completely flat (in fact usually I dismounted them from the frame an put them in a negative holder to partially correct it)

Could some field curvature have been bundled in the lens design?

This has been mentioned before and it make sense but with Scanner Nikkors and the Minolta scanner lenses and with the stage and the lens aligned, the frame with sharpest center is almost always the frame with the sharpest corner. Even with these lenses I still shoot a stack even though I usually only use one frame. This is my experience shooting way too many scanner lens test images, it has to be easily in the 1000s by now.

This is also the case with Line scan lenses like a Macro Varon, but a lens like a Canon MP-E or other consumer market lens will almost always have different frames for the sharpest corner and center images, some lenses need 3 or more images if you compare center, edge and corner.

All the best,

Robert

[RobertOToole]

Hi Daniel,

I tried again to compare the two positions of the Minolta 5400 objective. Since I have read that the original position in the scanner is what I have named „position 1“ (in my comparison pictures always on the left), but my stacking results yesterday have been better in „position 2“ (in my comparisons always on the right), I got curious.

This comparison shows that the objective can only be used in one direction, with the light entering on the side carrying the golden paint mark.

Very nice work Daniel, beautiful images, and nice and easy to read over even though I knew the answer before I got to the end.

Whenever I test any lens I always make sure to shoot a stack in both directions with a new lens, and I usually mention the direction used in the comparison.

I learned the hard way the dangers of about assuming I know the correct direction for the best image quality.

Robert