Setting Up An Enlarger For 16mm and Minox

[ic-racer]

Like some here, I have a lot of enlargers. A few were given to me, some purchased new and others purchased used.

I have never had a Minox enlarger, but I thought I could create one from what I have.

My two candidates were the Minolta Mod III and a Philips PCS 150.

Minolta Mod III is a good candidate because my 16mm cameras are Minolta and Minolta makes enlarging lenses for 16mm that fit that enlarger.

The Philips PCS 150 is a good candidate because I have the masking glass carrier for it, it is a condenser enlarger (maybe sharper??) and has an electronic color head that is pretty unique.

 

[ic-racer]

The design of both enlargers is about the same. The columns and baseboards are about the same size. Both are mostly aluminum construction with modern, late 70's styling.

The Philips was made in Europe and the Minolta made in Japan.

The Minolta color head is mechanical with subtractive dichroic filters and 35mm & 6x7 mixing boxes. The Philips color head is electronic additive 3-light system with 35mm and 6x7 condensers.

 

[ic-racer]

Two things favored the Philips.

The glass carrier has built-in masking blades and the focus knob has a second 'fine focus' geared knob. These two things will come in handy working with tiny negatives.

 

[ic-racer]

PSC 150 getting ready for a general inspection and cleaning.

 

[ic-racer]

Cleaning the mirror and associated components of the light assembly.

 

[ic-racer]

The door to access the condensers was stiff, so it required removing some material from the door area to make it easier to open and close.

 

[ic-racer]

I removed and inspected the light assembly. This is an additive head. Each lamp has a dichroic filter through which the light will pass. This is similar to the Ilford 500 Multigrade head (additive system of green and blue).
The lamp is a little odd but not hard to find replacements. All 3 were in good shape, but I have 3 spares also.

 

[ic-racer]

I used a laser to align the lens stage.

As a note to myself, I put Eneloop batteries in the laser. Those won't leak or loose charge.

 

[ic-racer]

One thing the Minolta enlarger has over the Philips is better adjustability. The Minolta lens stage has a 3-point adjustment for alignment.

The Philiips is 'aligned at the factory.' Even so , it was a little off for all these years.
In spite of not having an adjustment, frequently something can be found to make it correct. In this case the junction of the pivot for the lens swing (for correcting converging lines) would accept a shim of appropriate size to get the lens stage in alignment with the negative carrier.

 

[ic-racer]

Inspected, cleaned, aligned and almost ready to go.

 

[ic-racer]

The Philips came to me with glassless inserts for the negative carrier. Glass was an option.
I used some broken 4x5" Durst AN glass to make suitable glass. I cut the chipped 4x5" glass to the correct size and beveled the edges with a diamond bit grinding tool. Keeping the glass cool with a wet sponge during the process.

 

[ic-racer]

Some lens testing.

Schneider Componon-HM 45mm F4

vs

Minolta Rokkor-X CE 2.8 30mm

 

[Bill Burk]

I use a 28mm f/4 Rodenstock Rodagon on my Omega DII

For a while I used a tuna can lens mount, but found an Omega inverted cone (about the size of a tuna can).

 

[ic-racer]

I have an Omega Rodenstock "Omegaron" 25mm f4, but I don't think it is in the same league as the Rodagon and the others. It has been a while since I used it but I recall that if the negative is not centered to the sub-millimeter, one corner would be fuzzy. That is part of the paradox of enlarging tiny negatives. My shortest focal length (that might make the biggest enlargement) is unsuitable for anything larger than 4x5", and barely that even.

To make my standard 4x6" print (on 8x10 paper) the Componon-HM 45mm requires the enlarger head to be at the top of the column.
To make the same 4x6" print with the 30mm Rokkor-X CE, the enlarger column is about half-way up.

The Componon-HM is clearly superior under the Peak magnifier. It is probably the best "50mm" enlarging lens ever made.

However, the Philips enlarger has only tiny 30W lamps. So using the Componon-HM wide open (it is perfectly sharp across the entire minox field even wide open) requires a printing time around 60 to 80 seconds with a typical multigrade printing light output (additive head).

 

[ic-racer]

The 30mm Rokkor-X CE at f2.8 is just slightly less sharp at the corners of the minox frame compared to the Componon-HM. However, the convenience of printing at 30 to 40 seconds may outweight this slight loss of corner resolution.

Examining prints with a magnifier, again gives a slight advantage at the corners to the Componon-HM (both lenses wide open), but at a reasonable viewing distance, there is no difference between the prints with the two lenses.

My Rodenstock Omegaron 25mm f4 is a 30mm mount, I have a washer and mounting ring, so I may be able to mount the lens. However for it to provide any level of performance at f4, it will have to be perfectly aligned with the lensboard to the sub millimeter. May not focus, however.

On my Omega, I do similar to Bill and use an inverted lens cup, but this whole thread is about NOT using the Omega D5500 anymore for Minox; No reason really, other than for something interesting to do with some of my spare enlargers.

 

[ic-racer]

First prints with Hp5 split with my stainless steel Minox splitter are not so good.
Exposure of the Hp5 was EI 200 and development time was 6 minutes with the same chemistry volume used for 80 square inches of film.

The negatives are both over-exposed and over developed. They fall way off the end of the "Exposure vs Print Quality" curve. In the graph below the would be at "10X extended development."

 

[ic-racer]

Anyone doing small format photography needs to know what the detrimental effects of over exposure and over development do to an image. Because the prints appear to suffer from any combination of camera shake, poor camera focus, diffraction and or severe chromatic aberration, when none of these entities actually existed at the time of exposure.

 

[Bill Burk]

Nice analysis. I used a 50mm Omegaron as my “best” lens for many years, so your 25mm f/4 may surprise you.

 

[Patrick Robert James]

I converted (temporarily) my focomat 1c for Minox before i bought a Minox enlarger on Craigslist for a whopping $25. The biggest problem is of course the amount of light going through the tiny neg. I sort of solved that issue with a projection type frosted LED bulb which improved the exposure into a doable range. I was able to use a Minolta 30mm lens with the Focomat. I also had a glass carrier that I made to hold the neg. Worked pretty good in the end. The Minox enlarger is of course a lot easier to use... I was able to get full 6x9 ish prints out of the focomat/Minolta combo with some room to spare.

I think the 30mm Minolta is decent but not as good at their 50 for whatever reason. I recently took it apart and cleaned it and made sure it was put together correctly. Maybe that will improve it. I didn't have any issues with edge sharpness but I do align my enlargers down to the nth degree with a laser. It has a little more contrast than the Minox lens but the Minox lens seems to have slightly more resolution. I'll post an example.

I've been thinking about building a light source that would fit my Saunders 4550 in place of the mixing box, which should be reasonable easy to do. The little Minox negs need a lot of light... When I gave the Saunders a whirl my exposure times were way north of a minute even for very small prints, and that was using the 35mm mixing box too.

 

[Patrick Robert James]

Here is a comparison. The Focomat/Minolta lens is on the left and the Minox enlarger is on the right. Ignore the splotchiness of the Minox enlarged print. I messed up the neg but this is the only image that I've enlarged on both. You can see though that the Minolta has slightly more contrast and the Minox has slightly more resolution. They were both printed at grade 5 only (through the same blue filter). These are just screen captures...

 

[ic-racer]

Nice comparison, thanks for posting.

 

[ic-racer]

I was just using this enlarger for Minox today and had an idea to shorten printing times for Lith printing.
Since the RED light does nothing in B&W, I thought I'd put it to work.
By removing the RED filter, the third light can just be white light.

 

[Patrick Robert James]

You could pull the other two then use below the lens filters. Minox sure needs a lot of light.

How is that working out for you by now ic-racer?

I am still looking for a wider lens to print Minox. I was thinking about one of the Voigtlander LTM lenses, like the 12 or 15mm. Might work ok since we are only using the center and the neg is so small. One of these days...

Post some pics when you get a chance. I'd love to see them.

 

[xkaes]

I have an Omega Rodenstock "Omegaron" 25mm f4, but I don't think it is in the same league as the Rodagon

Optically they are the same. It's just that Omega was the initial distributor of Rodenstock lenses -- and wanted their name attached. When Rodenstock dropped Omega (or vice-versa), Rodenstock changed the name. Then they came out with the Rodagon-S -- which is also the same, but in an untapered body.

 

[xkaes]

My Rodenstock Omegaron 25mm f4 is a 30mm mount

That should be 32.5mm. I've never seen one with a 30mm thread.