And there it is. The Tamron SP 90/2.8 Macro (017) is much better covering the larger Fujifilm GFX sensor when scanning 6x7 negatives (which isn't at real Macro 1:1 but a lot less). Compared with the Sigma 70/2.8 ART Macro.

Both lenses were stopped down to ƒ9 in this comparison:

Tamron SP 90 mm ƒ2.8 VC (F017) Macro at aperture ƒ9.0 with Fujifilm GFX 50s II (photo of a 6x7 negative)

Sigma 70mm ƒ 2.8 ART Macro at aperture ƒ9.0 with Fujifilm GFX 50s II (photo of a 6x7 negative)

Tamron 90/2.8 Macro wins

A clear winner is the TAMRON SP 90/2.8 VC MACRO lens (version 2, F017)

• The Tamron 90 does NOT extend physically when you change focus manually, while scanning 6x7 negatives with the VALOI 120 or VALOI 135 scanning devices. This is certainly a great advantage !

• The Sigma 70 Macro inner lens barrel (the one that moves when focusing) - is the only place where you can to adapt something to it. The larger outer barrel also has a thread - but there are no step-rings in that size. (it lies somewhere between 62 and 67 mm). VERY STUPID !

Therefore a large scanning device like the VALOI 120 and its weight is directly connected to the moving inner barrel of the Sigma 70 lens. When you want to change focus - something has to move with it; either camera or VALOI 120. So, you need to wiggle one of them somehow, in order to set focus.

• If you use other means to scan negatives (such as putting your camera on a tripod / repro or enlarger board , physically extending macro lenses do not pose any problems). Then you have more options of macro lenses, too. Like Pentax 645 120mm Macro, which covers the larger Fujifilm GFX sensor just fine without any hints of corner shading. like for all 645 mediumformat Macro lenses, having a larger image circle covering the Fujifilm GFX image sensor.

• The Tamron 90 does NOT vignette in the extreme corners at close focus range and when stopped down (Truly excellent performance in that regard). The Sigma 70 on the other hand, vignettes pretty badly, in the extreme GFX corners).

• Both lenses render sharp into the corners. Though, Sigma 70 is a tiny notch sharper.

• The VALOI 120 device (its negative carrier/frames) are flawed in their design, because you get ONLY flat negatives when the entire film remains UNCUT. Which, let's face it, is highly unrealistic that anyone would ever want to store all their 120 mediumformat films in an uncut state.

How else are you going to store mediumformat negatives over the years ?!

Why was this knowledge overlooked by or in the creation of VALOI 120 ? We all cut negatives down, because that is the most sensible thing to do, when storing them in a practical manner - in negative folders. But cut negative stipes do not get sharp entirely - because they are not being held entirely flat in the VALOI film holders.

Then - for whom is the VALOI 120 device - when flatness isn't ensured for cut negatives ? The usefulness of the expensive VALOI 120, is then only for uncut films. But that doesn't make sense in the long haul.

Flatness of negatives is a No 1 mandatory requirement for everything revolving negatives. Whether you enlarge them for printing, or scan them in order to make digital copies. They always need to be 100% flat.

VALOI 120 holders do not do that. Only when the film negative remain uncut.

Most photographers want at some point to re-scan negatives (for example when you get a better camera or macro lens) But then you will likely have your negatives cut down. What about negatives from the past !? They are all cut down into stripes. All who love mediumformat photography - cut down film into negative stripes.

That's reality.

The VALOI 120 however, does not deliver absolute flatness for the millions of cut negative stripes out there.

FINAL:

All film holders for the VALOI 120 have a very serious design flaw in their current state. They only produce flat negatives scans when the entire film remains uncut.

For cut negatives, the holders are mediocre at best - and you get blurry borders / corners.

The VALOI is not a cheap device - it costs considerably (7000 SEK / 650 Euro), but serves extremly few from an already small group of serious, analog photographers. It serves basically basically only people who have uncut 120 film rolls.

But who does that ? I know nobody and have never met anyone.

 

Facit • Sigma vs Tamron Macro lenses

Two Macro lenses - but once performs admirably well for scanning negatives with a Fujifilm GFX camera.

Both are sharp - yes - perhaps with the Sigma ART Macro 70 having a slight edge at ƒ9 aperture. This however irons out when you apply a tiny bit of extra sharpness in your scanned negatives with the Tamron SP 90.

The Sigma 70 however is quirky when it comes to corner shading - as it does not cover the GFX sensor fully. (Sometimes at certain distances it does, while when focusing close, dark corners do appearmore pronounced)

The Tamron vignettes with soft darker corners at infinity and a bit closer - but once you focus really close, including down to 1:1 - and stop the aperture down it is nearly free from dark corners.

Well then.

What if ?

Using the Sigma ART 70/2.8 on the GFX camera anyway for scanning 6x7 negatives ?

You simply have to make the negative a bit smaller - so that the worst part of the dark corners can be cut off. Then, the tiny rest that remains can be corrected much better.

I mean, that's how i have been doing it for a couple thousands scans recently.

In the mean time, I am sending back the faulty Tamron SP 90/2.8 Macro lens to the bank shop where i bought it from. I just got the notification about that. The question however is, will i be re-buying that lens from Japan instead ? it would cost me even more than 360 €, due to the taxes.

I have not yet made up my mind. First i send the Tamron back, and get my money. Then I'll see how I proceed. I could continue with the Sigma 70 ART Macro - i know the quirks by now. Will see... I have not decided yet.

One step at the time.