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Adapting Kodak Aero Ektar 178mm to Fuji GFX-50R Help
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PostPosted: Sat May 11, 2019 9:58 pm    Post subject: Adapting Kodak Aero Ektar 178mm to Fuji GFX-50R Help Reply with quote

Hi all,

I recently got an Aero EKtar 178mm f/2.5 lens. It was new old stock and is in about perfect condition. I wanted to adapt it to the Fuji GFX-50R but I'm struggling with figuring out the proper adapter setup to get it there. For now I've ordered a tube adapter that fits the unusual thread size of it and brings it down to M65. From there, I was going to get an M65 to M65 focusing helicoid and then a 1mm thick M65 to Fuji GFX adapter. The main adapter that brings it down to an M65 thread mount measures 55mm and the 1mm final adapter to the camera means the length of the tube is a current 56mm. W\th that in mind, what size focusing helicoid should I be considering?


PostPosted: Sun May 12, 2019 1:51 am    Post subject: Reply with quote

I wish I had an Aero Ektar... I often mount press camera and LF lenses to my Nikon DSLR. I use a macro bellows for focusing but a helicoid would work too. Typically, I find a filter adapter ring (step up/down) that will slide over the lens mount and attach it with the lens lock ring. I then mount the adapter ring to a Nikon BR-2 lens reversing ring and attach to the bellows. The Aero Ektar may be a little big for the filter adapter so you will need to get creative. I have used old lens hoods to adapt bigger lenses.
Hope to see some pics from the Aero Ektar




PostPosted: Mon May 13, 2019 3:32 pm    Post subject: Re: Adapting Kodak Aero Ektar 178mm to Fuji GFX-50R Help Reply with quote

mackeral wrote:
I recently got an Aero EKtar 178mm f/2.5 lens. It was new old stock and is in about perfect condition. I wanted to adapt it to the Fuji GFX-50R but I'm struggling with figuring out the proper adapter setup to get it there. For now I've ordered a tube adapter that fits the unusual thread size of it and brings it down to M65. From there, I was going to get an M65 to M65 focusing helicoid and then a 1mm thick M65 to Fuji GFX adapter. The main adapter that brings it down to an M65 thread mount measures 55mm and the 1mm final adapter to the camera means the length of the tube is a current 56mm. W\th that in mind, what size focusing helicoid should I be considering?


There may be several versions of the Aero Ektar 178mm f/2.5 around, but at least for one I have come across the measurement of 125mm as the as the required distance between the rear of the lens and the film / sensor. If that is the case for your lens as well, then 125 - 56 - 27 (flange distance of the GFX) would result in a minimum size of 42mm for the helicoid. Annoyingly this would make the 45-95mm helicoid just bit too long to reach infinity focus. The best match may be the 25-55 helicoid, but this leaves you with just very few mm to actually focus with, just the 13mm from 42 to 55mm. Anyway, the measurement of 125mm may not be correct for your lens, and I don't know whether the rear of the lens and the attachment point of your tube adapter coincide (probably not). So maybe you need a longer helicoid, in which case the 45-95 would be ideal.


PostPosted: Mon May 13, 2019 3:47 pm    Post subject: Re: Adapting Kodak Aero Ektar 178mm to Fuji GFX-50R Help Reply with quote

dickb wrote:
mackeral wrote:
I recently got an Aero EKtar 178mm f/2.5 lens. It was new old stock and is in about perfect condition. I wanted to adapt it to the Fuji GFX-50R but I'm struggling with figuring out the proper adapter setup to get it there. For now I've ordered a tube adapter that fits the unusual thread size of it and brings it down to M65. From there, I was going to get an M65 to M65 focusing helicoid and then a 1mm thick M65 to Fuji GFX adapter. The main adapter that brings it down to an M65 thread mount measures 55mm and the 1mm final adapter to the camera means the length of the tube is a current 56mm. W\th that in mind, what size focusing helicoid should I be considering?


There may be several versions of the Aero Ektar 178mm f/2.5 around, but at least for one I have come across the measurement of 125mm as the as the required distance between the rear of the lens and the film / sensor. If that is the case for your lens as well, then 125 - 56 - 27 (flange distance of the GFX) would result in a minimum size of 42mm for the helicoid. Annoyingly this would make the 45-95mm helicoid just bit too long to reach infinity focus. The best match may be the 25-55 helicoid, but this leaves you with just very few mm to actually focus with, just the 13mm from 42 to 55mm. Anyway, the measurement of 125mm may not be correct for your lens, and I don't know whether the rear of the lens and the attachment point of your tube adapter coincide (probably not). So maybe you need a longer helicoid, in which case the 45-95 would be ideal.


Thanks so much! Once I get the adapter that brings it down to M65, I'll post some photos of it and where I'll be going with it. Hoping for the best on it but thanks for the info as it helps immensely.


PostPosted: Mon May 13, 2019 7:01 pm    Post subject: Reply with quote

I have an old Aero Ektar. Perhaps it is very sharp, BUT IT IS HUGE for mirrorless cameras. Also it is radioactive.


PostPosted: Mon May 13, 2019 7:10 pm    Post subject: Re: Adapting Kodak Aero Ektar 178mm to Fuji GFX-50R Help Reply with quote

mackeral wrote:
Thanks so much! Once I get the adapter that brings it down to M65, I'll post some photos of it and where I'll be going with it. Hoping for the best on it but thanks for the info as it helps immensely.


You're welcome. If you already have the lens and the camera, you can obviously test it by handholding the lens in front the camera.

I came across a site with more details:

http://www.johndesq.nl/graflex/fastlane.htm

This site mentions a back focus of 122.8 mm and that it is lens specific. The rear diameter of the lens is 74mm and looking at the pictures there is a thread of around 78mm where the original mounting surface would be. I am not sure whether the back focus measurement is taken from the rear of the lens or the mounting thread. I take it your adapter screws into those threads? If yes, than maybe you have a few more cm to play with, that is, if the back focus measurement is indeed taken from the rear of the lens.

I have used a few 58mm diameter chinese helicoids and those had a bit more play than I would have liked. With the ones labelled as having a brass helicoid the play is only in the Z axis. As your lens is pretty heavy, constructing some sort of tripod mount on the lens may be useful. And finally a small but essential thing to check when combining threaded adapters and helicoids and such, do all the male/female threads line up correctly? In M65 I know of no male/male or female/female rings, so getting it right the first time is useful..


PostPosted: Tue May 14, 2019 5:35 pm    Post subject: Re: Adapting Kodak Aero Ektar 178mm to Fuji GFX-50R Help Reply with quote

dickb wrote:
mackeral wrote:
Thanks so much! Once I get the adapter that brings it down to M65, I'll post some photos of it and where I'll be going with it. Hoping for the best on it but thanks for the info as it helps immensely.


You're welcome. If you already have the lens and the camera, you can obviously test it by handholding the lens in front the camera.

I came across a site with more details:

http://www.johndesq.nl/graflex/fastlane.htm

This site mentions a back focus of 122.8 mm and that it is lens specific. The rear diameter of the lens is 74mm and looking at the pictures there is a thread of around 78mm where the original mounting surface would be. I am not sure whether the back focus measurement is taken from the rear of the lens or the mounting thread. I take it your adapter screws into those threads? If yes, than maybe you have a few more cm to play with, that is, if the back focus measurement is indeed taken from the rear of the lens.

I have used a few 58mm diameter chinese helicoids and those had a bit more play than I would have liked. With the ones labelled as having a brass helicoid the play is only in the Z axis. As your lens is pretty heavy, constructing some sort of tripod mount on the lens may be useful. And finally a small but essential thing to check when combining threaded adapters and helicoids and such, do all the male/female threads line up correctly? In M65 I know of no male/male or female/female rings, so getting it right the first time is useful..


The adapter I've ordered is this:

https://www.ebay.com/itm/Aero-Ektar-lens-to-M65x1-male-thread-adapter/253592399600?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I beleive it's specifically designed to get the lens to a more manageable M65 thread. My though was to get an M65 to M65 Helicoid of which there are many options on eBay, but I wanted to get that adapter first to see how it works with the lens.


PostPosted: Tue May 14, 2019 7:44 pm    Post subject: Reply with quote

I took it out of the K-24 camera (which is a beast and an amazing piece of kit in itself).

The glass has some browning which I can address at some point but it doesn't seem extreme to me. Though I'm not sure what the normal amount of browning is for these.

The numbers all match and the interesting thing is the mark that says, "BF 127.0 mm" or maybe "122.0 mm?" which I believe to indicate Back focus at 127mm. I've attached images for reference.













PostPosted: Wed May 15, 2019 9:28 am    Post subject: Reply with quote

mackeral wrote:

Back Focus=122mm, it's written on the lens.

Cheers!

Abbazz


PostPosted: Wed May 15, 2019 12:35 pm    Post subject: Reply with quote

I would read it as 122 as well. Anyway, this is easy to test, just project an image with the lens and measure how far behind the lens the image on infinity is formed. This will also tell you whether the back focus is measured from the rear of the lens or the intended mounting plane. This makes a big difference in the length of helicoid you will need.


PostPosted: Thu May 16, 2019 5:24 pm    Post subject: Reply with quote

So basically I would subtract the flange distance of my camera (Fuji GFX-50r) from that 122mm? And then proceed to make a tube as equal to the remaining measurement? The flange distance would be 26.7mm so 95.3mm to go?


PostPosted: Thu May 16, 2019 6:42 pm    Post subject: Reply with quote

mackeral wrote:
So basically I would subtract the flange distance of my camera (Fuji GFX-50r) from that 122mm? And then proceed to make a tube as equal to the remaining measurement? The flange distance would be 26.7mm so 95.3mm to go?


Yes, but the question is where that 122mm is measured from. Most likely it is from the threads where the lens would be connected to the camera, that makes most sense as being referred to as the flange in the flange distance. But like I said a few times before, just measure the distance behind the lens the image is formed when focussed on infinity, the easiest subject would be the sun. This will give you the exact distance for your lens. As your lens has a very long thread, the RAF adapter may not reach the front of the threads, so if the flange distance is measured from the front of the thread you still don't have an exact distance to calculate. In that case the length of tube you want between Raf Adapter and M65 to GFX adapter is 122 minus 27 for the GFX register, minus 57 for the RAF adapter and minus x mm for the difference in where the adapter screws onto the thread and the location where the flange is measured from. So that would leave you with 95.3-56, so 39mm minus x.


PostPosted: Fri May 17, 2019 9:07 pm    Post subject: Reply with quote

The RAF adapter arrived. It's a fairly solid piece of kit. The adapter screws all the way to the top of the threads on the Ektar so that's good. I see what you mean about the back of the lens not going right up to the back of the tube as seen with the red arrows in the pic. At least I think that's what you meant. I'll be doing some tests today and already free-lensed it for fun but it's gradually getting there. Thanks again and I'll update as it progresses. Also, the suggestion for a tripoid clamp is definitely a good one. Looking into that too.





PostPosted: Sat May 18, 2019 12:16 pm    Post subject: Reply with quote

mackeral wrote:
The RAF adapter arrived. It's a fairly solid piece of kit. The adapter screws all the way to the top of the threads on the Ektar so that's good. I see what you mean about the back of the lens not going right up to the back of the tube as seen with the red arrows in the pic. At least I think that's what you meant.


From the technical drawing I couldn't tell how far up the thread the adapter could screw, indeed. Just to be sure, on the 77.5mm thread of the Aero Ektar, is there a still an original retaining ring screwed onto it? From your photos I can't tell whether it is a ring or a fixed piece of barrel. If yes, you could remove it so you could screw the adapter all the way to rear of the lens. Alternatively, you can use the ring to adjust the infinity setting on your fianl lens / adapter/ helicoid combo.

mackeral wrote:
I'll be doing some tests today and already free-lensed it for fun but it's gradually getting there. Thanks again and I'll update as it progresses.


Have fun with it.

mackeral wrote:
Also, the suggestion for a tripoid clamp is definitely a good one. Looking into that too


You could try cheap chinese tripod adapters intended for larger DSLR lenses. Depending on the outer diameter you could get some of these described on Pentaxforums:

There are a range of very cheap, typically Chinese made, alloy tripod collars available. They are often described as being for Canon lenses eg a 66mm ID hinged one is described as for 70-200mm f4/Canon EF 300mm F4L/Canon EF 400mm F5.6L lenses.
UPDATE with a bit of browsing these are some of the ones available. ID = inside diameter; H/NH = hinged/not hinged, price approx in UK£ - UPDATE Feb '17 prices (UK) are higher now.

ID: H/NH material Described as for: price
65mm; 66mm H Alu Canon 70-200mm f4; EF 200mm; EF 300mm., EF 400mm ~ 5
68; 69mm H Alu Canon EF 100mm f2.8L macro IS 7 - 10
68.5mm H abs Canon EF 70-200mm f/2.8L USM, Canon EF 70-200mm f/2.8L IS USM 5
70mm NH Alu Canon EF 100mm f2.8 IS USM 10
71mm NH Alu Canon 100mm 2.8 micro ("old") 3 - 4
72mm H Alu Canon 180mm macro, 65mm macro 11
77mm/78mm NH Alu Canon 70-200mm f2.8 5-10
81mm H Alu Canon EF 28-300mm f3.5-5.6 10
81/81.5mm H Alu Canon 70-300mmf4-5.6L IS USM 10-20
80mm/82mm NH Alu Nikon AFS 80-200mm 12
I have found these particularly useful to use, or adapt to use, with my Tamron adaptall lenses. As is the 66mm one is just about spot on to fit around the 01F TC (update most need a little packing). I find they are pretty solid items.

Read more at: https://www.pentaxforums.com/forums/114-maintenance-repair-articles/238879-modding-chinese-other-tripod-mounts-fit-eg-adaptall-lenses.html#ixzz5oHHoSwxh