Favourite light and small lenses for GFX

[Rob de Loe]

Lenses for medium format tend to be large -- especially Fuji GF lenses. It's all relative of course, but I do find GF lenses to be on the "chonky" side. Sometimes I just want to throw a camera over my shoulder, and not feel like I'm carrying a briefcase.

Do you pine for a light and tiny lens for GFX cameras? If so, here's mine:


My favourite light, small lens

Oops, my bad. It's hidden behind that battery!

Here's my favourite light, small lens:


Now you can see it! Schneider-Kreuznach Apo-Componon HM 60mm f/4 in the Makro-Iris industrial mount.

That is one tiny lens: 118g, and sharp as can be from wide-open (f/4).

It's one of a set of Apo-Componon lenses I love using on my GFX. It's sibling, the Apo-Componon HM 90mm f/4.5 isn't much bigger. It too is a no-compromises lens that is terrific wide open.

These are both "rescues" by the way. They spent their previous life in a factory somewhere in Asia scanning printed circuit boards and getting no love whatsoever. They're much happier with me, where they get to go out and make pictures of all kinds of things (and never printed circuits). I know most people on this forum prefer pure bred lenses from a certified breeder like Fujifilm, but rescue lenses can give you a lot of joy too.

[ATTACH alt="Schneider-Kreuznach Apo-Componon HM 90mm f/4.5 with its slightly smaller sibling. Two of my "rescue" lenses."]2832861[/ATTACH]
Schneider-Kreuznach Apo-Componon HM 90mm f/4.5 with its slightly smaller sibling. Two of my "rescue" lenses.

Both of these lenses normally live on my Toyo VX23D outfit, but I've always wanted to use them directly on my GFX 50R. (Yes, I realize I have a superb GF 45-100/4... but look at the size of that thing!)

To use these little lenses directly on any camera, you need a focusing helicoid because the lens only has an aperture. Fortunately, it's not hard to cobble together what you need from inexpensive parts.


Adapter bits and pieces for focusing these lenses.

To use these lenses you just need to get them at their flange distance from the sensor (for infinity), and then move them farther from the sensor to focus more closely. Cheap Chinese helicoids to the rescue! The big one is an M65x1 helicoid. It's attached to a GFX to M65x1 adapter. The ring inset in the front of the helicoid is M65x1 gto M42x1. The lenses themselves use the Schneider-Kreuznach industrial "V-mount", so you have to add an adapter for either 39mm x 1/26th inch, or M42x1; I went with M42x1 for flexibility.

The little 60/4 lens screws directly onto the big helicoid. The 90/4 has a longer flange distance, so it needs some additional extension. I could have used tubes, but I went with a combination of a tube and an old Pentax M42x1 helicoid I had (which gives me extra extension for close focusing when I need it -- which I do all the time).

I did have to do a bit of light "machining" to get it all right, but for the main helicoid it was just a bit of sanding to take off a bit of thickness so the 60/4 lens would hit infinity.


OK, it's a little ungainly. I grant you that. But it's tiny and light, and it focuses beautifully!


Now we're talking ungainly! If you can get past the looks, this is a deadly sharp lens that performs as well at infinity as it does close-in. The second helicoid is there when I need extra magnification.

I could have used a smaller helicoid if these were the only two lenses I wanted to use directly. However, I went with M65x1 because I also wanted the option of using my Mamiya G 50mm f/4 and 150mm f/4.5. Those are also outstanding, no-compromise lenses that I use primarily on my GFX + Toyo VX23D outfit -- but with this design I can now use them directly on the GFX 50R too -- using the same adapter.


The Mamiya G lenses need one more adapter (the silver ring you can see at the base of the lens). That adapter weighs a few grams, and screws directly to the M65x1 helicoid; I don't remove the M65x1 to M42x1 insert.

Building this adapter for Mamiya G was a bit more work (some sanding, filing, drilling, and tapping). But it's worth the effort because those Mamiya G lenses are simply superb. Mamiya G lenses have their own focusing helicoids, but mine are a bit stiff with age so I just focus them from the big M65 helicoid.

View attachment 307250727cd14c648372d08963194828.jpg
SK Apo-CPN 60/4, at f/5.6 (full resolution JPEG)

 

[JimKasson]

You go, Rob!

 

[Greg7579]

I really enjoyed that! What and awesome post. I love it when you guys show your high-end, niche or retro gear and these little lenses are beautiful.

But Rob, the 45-100 is my number one by far favorite GF lens right now.

Are you trying to make me feel bad about myself?

I admit it ... Lugging the GFX 100 around all day with my favorite 45-100 can wear you out.

 

[Hamiltionian]

Nice work in getting those adapted. I always find those sorts of projects fun and gratifying, and you get a lens that no one else had.

Less ambitious, but also in the vein of the light and small lenses are the X-Pan lenses which have enough image circle to easily cover the 44x33 sensor. Image quality on the edges isn't great wide open though due to the short flange distance and thick hot mirror on the GFX cameras.





--
Stay Calm and Carry Cameras

The Center Column

Independent Tripod Testing

thecentercolumn.com

 

[Rob de Loe]

I really enjoyed that! What and awesome post. I love it when you guys show your high-end, niche or retro gear and these little lenses are beautiful.

But Rob, the 45-100 is my number one by far favorite GF lens right now.

Are you trying to make me feel bad about myself?

I admit it ... Lugging the GFX 100 around all day with my favorite 45-100 can wear you out.

The GF 45-100 is a stellar lens Greg. But I surely do notice it when I'm hauling that one around. And you carry it plus a bunch of other ones!

To be fair, my main setup is over 25 lbs of gear in a backpack. I don't enjoy carrying that thing around either. This new setup is for those times when I really do want to shoot the GFX using a pair of lenses that I can actually just drop in my pocket.

We're fortunate to have so many great options, both in pure breed and rescue lenses.

 

[Rich42]

My tiny EL Nikkor 50mm f/2.8 in its M42/helicoid/Nikon F adapter next to the 100s and GF 45/2.8.













I can mount the combo to the 100S with my Fotodiox Nikon F to GFX adapter, but that places the lens too far forward of its flange distance and all I can do is macro focusing.

I need a helicoid with a GFX mount directly on it.

And that, I can't find.

Rich

 

[Rob de Loe]

My tiny EL Nikkor 50mm f/2.8 in its M42/helicoid/Nikon F adapter next to the 100s and GF 45/2.8.

I can mount the combo to the 100S with my Fotodiox Nikon F to GFX adapter, but that places the lens too far forward of its flange distance and all I can do is macro focusing.

I need a helicoid with a GFX mount directly on it.

And that, I can't find.

Rich

Very nice Rich! I have a question and a tip now:

First, does that El Nikkor 50/2.8 cover the sensor? It's designed for 24mm x 36mm so I've never looked at it.

Second, if you're willing to throw a bit of money at the problem, there are solutions. RAF Camera in Moscow is superb. Raf will build you anything and his prices are extremely good.

Here for example is a M47x0.75 to M65x1 male thread adapter. He can make you this part with M42x1 instead of M47x0.75. This part would then drop into the M65x1 to GFX adapter that he sells. If you look at the diagram at the link, you'll see that this would buy you 11mm, which might be enough. If you've calculated that you need more, just ask him to increase the recession from 11mm to whatever you need. Just double-check that your M42 helicoid will fit into the opening. My M42x1 helicoid is diameter 58.68mm. The space inside the part at that link is 59.5mm -- so it would be close but it would fit. The other issue is will you be able to turn the helicoid ring. I could not turn mine because it would be all the way in. So it will be important to recess as little as is needed to reach infinity, i.e., if you don't need 11mm, get him to make it only as deep as needed.

Rob

 

[Rich42]

My tiny EL Nikkor 50mm f/2.8 in its M42/helicoid/Nikon F adapter next to the 100s and GF 45/2.8.

I can mount the combo to the 100S with my Fotodiox Nikon F to GFX adapter, but that places the lens too far forward of its flange distance and all I can do is macro focusing.

I need a helicoid with a GFX mount directly on it.

And that, I can't find.

Rich

Very nice Rich! I have a question and a tip now:

First, does that El Nikkor 50/2.8 cover the sensor? It's designed for 24mm x 36mm so I've never looked at it.

Second, if you're willing to throw a bit of money at the problem, there are solutions. RAF Camera in Moscow is superb. Raf will build you anything and his prices are extremely good.

Here for example is a M47x0.75 to M65x1 male thread adapter. He can make you this part with M42x1 instead of M47x0.75. This part would then drop into the M65x1 to GFX adapter that he sells. If you look at the diagram at the link, you'll see that this would buy you 11mm, which might be enough. If you've calculated that you need more, just ask him to increase the recession from 11mm to whatever you need. Just double-check that your M42 helicoid will fit into the opening. My M42x1 helicoid is diameter 58.68mm. The space inside the part at that link is 59.5mm -- so it would be close but it would fit. The other issue is will you be able to turn the helicoid ring. I could not turn mine because it would be all the way in. So it will be important to recess as little as is needed to reach infinity, i.e., if you don't need 11mm, get him to make it only as deep as needed.

Rob,

I don't know if the EL Nikkor will cover the GFX sensor as I can't mount it to find out!

I originally got the helicoid thinking the EL Nikkor would outperform my 105mm f/2.8 AF Micro Nikkor for digitizing film on my D800E. Boy, was I wrong. The Micro Nikkor outperformed it and the optical system in my drum scanner.

It would be interesting to use the EL Nikkor on the GFX 100S. But so far, going through all my lenses that I thought would be interesting to use as "adapted," including Pentax 67 lenses, a slew of process lenses and my Nikon 180/2.8, the only one worth going through the effort is the 180. The 180 is great. The Nikon 105 Micro Nikkor performs very well and has no vignetting in the macro range (which is where I use it on the Nikons, anyway because it's soft at distance)

I've been really, really happy with my small collection (soon to grow) of GF 45, 110 and Milvus 135 which have kept me far, far away from any adapted rig.

The 45/100S combination is really no heavier than my D850 and Nikkor 105. It's a pleasure to use. On any given day it's a battle between it and the 110 f/2, which one to use. These two lenses take no prisoners and instantly banish thoughts of anything non-GF!

But my Milvus 135/2 is also an "adapted lens" in the strict sense as it's in an F mount. And it is a whole other story. The only adjectives are superlatives. It's not a GF lens. It's in its own league. Different pedigrees. Top of the heap.

In the next six months or so I'll get the GF 23/2.8 and the 80/1.7. From 23 through 180 I don't think I'll be interested in other lenses for a while. ;-)

But the EL Nikkor plus its helicoid plus the Fotodiox F mount to GFX mount adapter is barely heavier than the 100S alone. I may pursue getting the EL Nikkor mounted as you've suggested. And if it vignettes, who cares?!

And then I can say, "I know a guy!"

In Moscow!

Rich

 

[Rob de Loe]

My tiny EL Nikkor 50mm f/2.8 in its M42/helicoid/Nikon F adapter next to the 100s and GF 45/2.8.

I can mount the combo to the 100S with my Fotodiox Nikon F to GFX adapter, but that places the lens too far forward of its flange distance and all I can do is macro focusing.

I need a helicoid with a GFX mount directly on it.

And that, I can't find.

Rich

Very nice Rich! I have a question and a tip now:

First, does that El Nikkor 50/2.8 cover the sensor? It's designed for 24mm x 36mm so I've never looked at it.

Second, if you're willing to throw a bit of money at the problem, there are solutions. RAF Camera in Moscow is superb. Raf will build you anything and his prices are extremely good.

Here for example is a M47x0.75 to M65x1 male thread adapter. He can make you this part with M42x1 instead of M47x0.75. This part would then drop into the M65x1 to GFX adapter that he sells. If you look at the diagram at the link, you'll see that this would buy you 11mm, which might be enough. If you've calculated that you need more, just ask him to increase the recession from 11mm to whatever you need. Just double-check that your M42 helicoid will fit into the opening. My M42x1 helicoid is diameter 58.68mm. The space inside the part at that link is 59.5mm -- so it would be close but it would fit. The other issue is will you be able to turn the helicoid ring. I could not turn mine because it would be all the way in. So it will be important to recess as little as is needed to reach infinity, i.e., if you don't need 11mm, get him to make it only as deep as needed.

Rob,

I don't know if the EL Nikkor will cover the GFX sensor as I can't mount it to find out!

I originally got the helicoid thinking the EL Nikkor would outperform my 105mm f/2.8 AF Micro Nikkor for digitizing film on my D800E. Boy, was I wrong. The Micro Nikkor outperformed it and the optical system in my drum scanner.

It would be interesting to use the EL Nikkor on the GFX 100S. But so far, going through all my lenses that I thought would be interesting to use as "adapted," including Pentax 67 lenses, a slew of process lenses and my Nikon 180/2.8, the only one worth going through the effort is the 180. The 180 is great. The Nikon 105 Micro Nikkor performs very well and has no vignetting in the macro range (which is where I use it on the Nikons, anyway because it's soft at distance)

I've been really, really happy with my small collection (soon to grow) of GF 45, 110 and Milvus 135 which have kept me far, far away from any adapted rig.

The 45/100S combination is really no heavier than my D850 and Nikkor 105. It's a pleasure to use. On any given day it's a battle between it and the 110 f/2, which one to use. These two lenses take no prisoners and instantly banish thoughts of anything non-GF!

But my Milvus 135/2 is also an "adapted lens" in the strict sense as it's in an F mount. And it is a whole other story. The only adjectives are superlatives. It's not a GF lens. It's in its own league. Different pedigrees. Top of the heap.

In the next six months or so I'll get the GF 23/2.8 and the 80/1.7. From 23 through 180 I don't think I'll be interested in other lenses for a while. ;-)

But the EL Nikkor plus its helicoid plus the Fotodiox F mount to GFX mount adapter is barely heavier than the 100S alone. I may pursue getting the EL Nikkor mounted as you've suggested. And if it vignettes, who cares?!

And then I can say, "I know a guy!"

In Moscow!

Rich

Sounds like you're good to go Rich.

I realized after posting the suggestion that if Raf was going to build you something, he could just build you a GFX to M42x1 adapter that is recessed enough for that lens.

However, I'm pretty sure I'm not wrong that it only covers 24mm x 36mm -- so it's going to vignette like crazy. In all my explorations, the widest enlarger/industrial lenses that cover are the 60mm ones. I've owned them all, and the Apo-Componon 60/4 is the best. Schneider sold it as the Apo-Digitar 60mm f/4 (different housing, and a lot more money!)

By the way, it's amazing what you can cobble together to test things without having to spend a lot of money on adapters. Before committing to buying the parts, I tried the 60/4 on this jury-rigged adapter. I used the flat plate from a GFX adapter, an M42 to EOS adapter, my M42 helicoid, and some gaffer tape. This test provided enough information to confirm it was worth proceeding.

 

[Rob de Loe]

You go, Rob!

Thanks Jim. I won't deny it's fun building these adapters and finding ways to make it work.

 

[JS6699]

My tiny EL Nikkor 50mm f/2.8 in its M42/helicoid/Nikon F adapter next to the 100s and GF 45/2.8.

I can mount the combo to the 100S with my Fotodiox Nikon F to GFX adapter, but that places the lens too far forward of its flange distance and all I can do is macro focusing.

I need a helicoid with a GFX mount directly on it.

And that, I can't find.

Rich

Very nice Rich! I have a question and a tip now:

First, does that El Nikkor 50/2.8 cover the sensor? It's designed for 24mm x 36mm so I've never looked at it.

Second, if you're willing to throw a bit of money at the problem, there are solutions. RAF Camera in Moscow is superb. Raf will build you anything and his prices are extremely good.

Here for example is a M47x0.75 to M65x1 male thread adapter. He can make you this part with M42x1 instead of M47x0.75. This part would then drop into the M65x1 to GFX adapter that he sells. If you look at the diagram at the link, you'll see that this would buy you 11mm, which might be enough. If you've calculated that you need more, just ask him to increase the recession from 11mm to whatever you need. Just double-check that your M42 helicoid will fit into the opening. My M42x1 helicoid is diameter 58.68mm. The space inside the part at that link is 59.5mm -- so it would be close but it would fit. The other issue is will you be able to turn the helicoid ring. I could not turn mine because it would be all the way in. So it will be important to recess as little as is needed to reach infinity, i.e., if you don't need 11mm, get him to make it only as deep as needed.

Rob,

I don't know if the EL Nikkor will cover the GFX sensor as I can't mount it to find out!

I originally got the helicoid thinking the EL Nikkor would outperform my 105mm f/2.8 AF Micro Nikkor for digitizing film on my D800E. Boy, was I wrong. The Micro Nikkor outperformed it and the optical system in my drum scanner.

It would be interesting to use the EL Nikkor on the GFX 100S. But so far, going through all my lenses that I thought would be interesting to use as "adapted," including Pentax 67 lenses, a slew of process lenses and my Nikon 180/2.8, the only one worth going through the effort is the 180. The 180 is great. The Nikon 105 Micro Nikkor performs very well and has no vignetting in the macro range (which is where I use it on the Nikons, anyway because it's soft at distance)

I've been really, really happy with my small collection (soon to grow) of GF 45, 110 and Milvus 135 which have kept me far, far away from any adapted rig.

The 45/100S combination is really no heavier than my D850 and Nikkor 105. It's a pleasure to use. On any given day it's a battle between it and the 110 f/2, which one to use. These two lenses take no prisoners and instantly banish thoughts of anything non-GF!

But my Milvus 135/2 is also an "adapted lens" in the strict sense as it's in an F mount. And it is a whole other story. The only adjectives are superlatives. It's not a GF lens. It's in its own league. Different pedigrees. Top of the heap.

In the next six months or so I'll get the GF 23/2.8 and the 80/1.7. From 23 through 180 I don't think I'll be interested in other lenses for a while. ;-)

But the EL Nikkor plus its helicoid plus the Fotodiox F mount to GFX mount adapter is barely heavier than the 100S alone. I may pursue getting the EL Nikkor mounted as you've suggested. And if it vignettes, who cares?!

And then I can say, "I know a guy!"

In Moscow!

Rich

Rich, what adapter do you use for the Milvus 135? Damn that lens has me drooling

Nevermind, just reread your post and saw the fotodiox reference.

 

[Rich42]

My tiny EL Nikkor 50mm f/2.8 in its M42/helicoid/Nikon F adapter next to the 100s and GF 45/2.8.

I can mount the combo to the 100S with my Fotodiox Nikon F to GFX adapter, but that places the lens too far forward of its flange distance and all I can do is macro focusing.

I need a helicoid with a GFX mount directly on it.

And that, I can't find.

Rich

Very nice Rich! I have a question and a tip now:

First, does that El Nikkor 50/2.8 cover the sensor? It's designed for 24mm x 36mm so I've never looked at it.

Second, if you're willing to throw a bit of money at the problem, there are solutions. RAF Camera in Moscow is superb. Raf will build you anything and his prices are extremely good.

Here for example is a M47x0.75 to M65x1 male thread adapter. He can make you this part with M42x1 instead of M47x0.75. This part would then drop into the M65x1 to GFX adapter that he sells. If you look at the diagram at the link, you'll see that this would buy you 11mm, which might be enough. If you've calculated that you need more, just ask him to increase the recession from 11mm to whatever you need. Just double-check that your M42 helicoid will fit into the opening. My M42x1 helicoid is diameter 58.68mm. The space inside the part at that link is 59.5mm -- so it would be close but it would fit. The other issue is will you be able to turn the helicoid ring. I could not turn mine because it would be all the way in. So it will be important to recess as little as is needed to reach infinity, i.e., if you don't need 11mm, get him to make it only as deep as needed.

Rob,

I don't know if the EL Nikkor will cover the GFX sensor as I can't mount it to find out!

I originally got the helicoid thinking the EL Nikkor would outperform my 105mm f/2.8 AF Micro Nikkor for digitizing film on my D800E. Boy, was I wrong. The Micro Nikkor outperformed it and the optical system in my drum scanner.

It would be interesting to use the EL Nikkor on the GFX 100S. But so far, going through all my lenses that I thought would be interesting to use as "adapted," including Pentax 67 lenses, a slew of process lenses and my Nikon 180/2.8, the only one worth going through the effort is the 180. The 180 is great. The Nikon 105 Micro Nikkor performs very well and has no vignetting in the macro range (which is where I use it on the Nikons, anyway because it's soft at distance)

I've been really, really happy with my small collection (soon to grow) of GF 45, 110 and Milvus 135 which have kept me far, far away from any adapted rig.

The 45/100S combination is really no heavier than my D850 and Nikkor 105. It's a pleasure to use. On any given day it's a battle between it and the 110 f/2, which one to use. These two lenses take no prisoners and instantly banish thoughts of anything non-GF!

But my Milvus 135/2 is also an "adapted lens" in the strict sense as it's in an F mount. And it is a whole other story. The only adjectives are superlatives. It's not a GF lens. It's in its own league. Different pedigrees. Top of the heap.

In the next six months or so I'll get the GF 23/2.8 and the 80/1.7. From 23 through 180 I don't think I'll be interested in other lenses for a while. ;-)

But the EL Nikkor plus its helicoid plus the Fotodiox F mount to GFX mount adapter is barely heavier than the 100S alone. I may pursue getting the EL Nikkor mounted as you've suggested. And if it vignettes, who cares?!

And then I can say, "I know a guy!"

In Moscow!

Rich

Rich, what adapter do you use for the Milvus 135? Damn that lens has me drooling

Nevermind, just reread your post and saw the fotodiox reference.

Yes, I'm using the Fotodiox adapter. But I don't like it.

It's strictly manual for both aperture and focusing (of course). The aperture settings are arbitrary, which they have to be as the adapter has no idea what the lens is doing and has to serve for any lens mounted. It kinda works.

I'll be getting the Steelsring adapter when it becomes available (heard its been back-ordered a while). It's expensive (somewhat more than $500), but what isn't in MF land? It will allow the camera to set the aperture (and allow AF with Nikon lenses that have internal motors).

Rich

 

[Rob de Loe]

Nice work in getting those adapted. I always find those sorts of projects fun and gratifying, and you get a lens that no one else had.

Less ambitious, but also in the vein of the light and small lenses are the X-Pan lenses which have enough image circle to easily cover the 44x33 sensor. Image quality on the edges isn't great wide open though due to the short flange distance and thick hot mirror on the GFX cameras.

I haven't had a chance to try X-Pan lenses. I just looked up the prices. Whoa. Which one do you have in this picture? I notice they have a 45/4, which is a focal length I like. Alas that flange distance of 34.27mm puts these out of reach for my VX23D outfit. It's nice to see that you can still keep them running with what looks like a good adapter on your GFX.

 

[Navman]

Rob, thanks for this very useful post. I have a 60/4 Componon that I've been getting frustrated with when using it on my GFX via FD extension tubes and an FD adapter. I had been looking at a Pentax 645 helicoid, but hadn't realised that they were also available with an M65 thread. Looking online, I've found helicoids with two options for degree of extension, i.e. one with extensions of 17 to 31 mm and another with 25 to 55 mm. What size did you use with your setup?

-John

 

[lottic]

I see no love for the 50mm f/3.5 here.

It's a stellar lens and stylish to boot.

 

[IacoPolo]

I see no love for the 50mm f/3.5 here.

It's a stellar lens and stylish to boot.

I love it. It’s the lens I use the most. Well, the only other one I own is the GF 30mm.

--
IacoPolo

 

[debo]

It’s an amazing lens. It’s even more compact when attached to a 100s due to IBIS. With my 50r it feels like a funk x100MF. Just posted a blue hour pic with the 50R.



Sfuff just pops out wide open.

 

[lottic]

An X100MF, now that sounds like a great idea Fujifilm :-D

 

[Rob de Loe]

Rob, thanks for this very useful post. I have a 60/4 Componon that I've been getting frustrated with when using it on my GFX via FD extension tubes and an FD adapter. I had been looking at a Pentax 645 helicoid, but hadn't realised that they were also available with an M65 thread. Looking online, I've found helicoids with two options for degree of extension, i.e. one with extensions of 17 to 31 mm and another with 25 to 55 mm. What size did you use with your setup?

-John

Hi John,

It's a superb lens and worth mounting. The lens cells in the three versions I'm aware of are all the same: Apo-Componon HM (enlarger mount), Apo-Componon HM (Makro-Iris mount, the one I have), and Apo-Digitar.

To determine the parts you need, you have to keep some numbers in mind:

• Lens flange distance is 53.29mm
• GFX flange distance is 26.7mm

That means you have 26.59mm for all parts of the mount (reason being that you'll want to be able to focus at infinity).

I bought the parts on eBay from iscope2011. There's another seller called hunter20099 that sells many of the same parts; it's the same people running two accounts!

• GFX to M65x1 adapter
• M65x1 to M65x1 focusing helicoid, 17-31mm
• M65x1 to M42x1 adapter ring.

If your lens is the enlarger variant, then you'll also need an adapter ring that converts your 39mm x 1/26th inch thread to M42x1.

The GFX to M65x1 adapter uses up 7mm of the 26.59. The helicoid uses 17mm. The M65x1 to M42x1 adapter actually gives you back around 2.3mm because it screws down below the face of the helicoid. Finally, the ring that converts the 39mm x 1/26th inch mount to M42x1 doesn't add/subtract any distance.

26.59-7-17+2.3 = 4.89

What this means is with this setup, you have to extend the helicoid by 4.89mm to be at the correct flange distance for infinity focus. That means you have 31-17-4.89 or 9.11mm of extension remaining. That's enough to allow you to focus from infinity down to 0.22m, which is very nice if you like close-in work.

If you had an extension tube that was exactly 4.89mm long, you would be able to focus even closer because you wouldn't need to use up any of the helicoid's extension to get to infinity.

Now, keep in mind that there are lots of other options, and you can use the same math as above to work out if they work. For example, you can get helicoids in M58x0.75, M52x0.75 and M42x1 sizes. I went with M65x1 for three reasons:

• It's the most common, so parts are readily available;
• I needed the room to adapt my Mamiya G lenses to the same unit (see picture in above post);
• I like a nice big ring. I find using M42 helicoids (even a good one like the Pentax version I have) to be harder because the ring you have to turn is tinier.

I hope that helps.

Rob

 

[goodbokeh]

A very imaginative and creative post and collection of glass Rob.

I've taken the road more traveled with GF lenses (so far). Like lottic and Iaco Polo, the small lenses that I enjoy are the GF50 for a single lens carry and the GF30 for when I'm taking a second Fuji APS-C or M10M body with a longer focal length prime. Both of these lenses transform my 100S into a very comfortable and sustainable carry for this 66 year old.

I'm intrigued about the upcoming GF 35-70 collapsible kit lens.