NF-GFX Fringer AF Performance On GFX50S

[Batdude]

I'm completely new to this system and I'm learning as I'm going.

I just got the Fringer adapter and I'm not very pleased with it. AF performance is not that great. My main dislike is that it hunts a bit too much. The GF 35-70 is really snappy, but other super expensive GFX native lenses are not fast either. I'm wasn't expecting for the Fringer to drive my Nikkor lenses as fast as if they were on my Nikon bodies, but I did expect more decent performance. Simple as that.

I have been writing to Fringer and this is what they told me: "As for AF performance, since you are using GFX50s which don't support PDAF, low AF performance is normal. Many SLR lenses were designed for PDAF only. Contrast AF is much slower and error-prone on them. If you do want SLR-like AF performance, you may consider GFX100 or GFX100S."

Will Fringer be capable of improving AF in the near future with this adapter, that I have no idea, but the support person doesn't sound very optimistic.

Is it true that if I had a GFX100 series my Nikkor lenses work better?

Having said that, if I end up returning this NF-GFX adapter, is there any option like getting a different mount with different brand lenses that perform much better? What options do I have?

Worst case scenario I'll just return the adapter and shoot manual, or keep this adapter and such it up hahaha!

Thanks

 

[Batdude]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

 

[Discombobulated]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

 

[koweb]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

 

[JimKasson]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

There’s no glass in that adapter, right? So f/2 is still f/2. Or are you asking about FF equivalence?

 

[Batdude]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

There’s no glass in that adapter, right? So f/2 is still f/2. Or are you asking about FF equivalence?

Mmmm is that a trick question or something?

All I'm asking is what the facts are, because I don't know, whether is FF equivalence or whatever. I just need to know so that I can start getting used to this and apply the correct multiplication or get the idea in my head and avoid opening the lens way too much, or vise versa.

Thanks.

 

[JimKasson]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

There’s no glass in that adapter, right? So f/2 is still f/2. Or are you asking about FF equivalence?

Mmmm is that a trick question or something?

All I'm asking is what the facts are, because I don't know, whether is FF equivalence or whatever. I just need to know so that I can start getting used to this and apply the correct multiplication or get the idea in my head and avoid opening the lens way too much, or vise versa.

If you set the aperture to f/2 , that’s what you’ll get. It will have the same DOF for 3:4 images as a FF f/1.4 lens.

Equivalence

--
https://blog.kasson.com

 

[VoltMan]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

There’s no glass in that adapter, right? So f/2 is still f/2. Or are you asking about FF equivalence?

Mmmm is that a trick question or something?

All I'm asking is what the facts are, because I don't know, whether is FF equivalence or whatever. I just need to know so that I can start getting used to this and apply the correct multiplication or get the idea in my head and avoid opening the lens way too much, or vise versa.

If you set the aperture to f/2 , that’s what you’ll get. It will have the same DOF for 3:4 images as a FF f/1.4 lens.

http://www.josephjamesphotography.com/equivalence/
--
https://blog.kasson.com

Thanks for the reference- I’ll be sure to make a New Year’s goal for 2023 to read and understand it

 

[Discombobulated]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8



now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

 

[JimKasson]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

 

[Batdude]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

 

[JimKasson]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

By any chance has anyone ever made a helpful chart or are there any out there on the internet that you like to reference to?

Like this

FF equivalent focal lengths of Hasselblad XCD, Fuji GF lenses - the last word

The question of equivalent full frame focal lengths of the Fujifilm GF and Hasselblad XCD lenses comes up over and over. I thought I'd post that information here, and then I can link to it when the topic comes up again. There are three common ways to calculate equivalent focal lengths: by sensor...

blog.kasson.com

but with f-stops?

 

[koweb]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

Exactly my point.

 

[Discombobulated]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

Exactly my point.

Sorry about my typo, fat fingers on tiny iphone.

MTF -> APS-C -> FF -> MF crop factor is supposedly consistent. I have no idea why these guys here suddenly say no crop factor from FF to MF. Often time on the internet people refuse to believe aperture is also affected by crop factor and it’s happening again.

 

[Dinomalichela]

I presume you havent got it to perform like your Pentax, Nikon ,Canon and Sony...And the colors stil not to your expectation?

 

[JimKasson]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

Exactly my point.

Sorry about my typo, fat fingers on tiny iphone.

MTF -> APS-C -> FF -> MF crop factor is supposedly consistent.

Crop factor can vary depending on calculation method if aspect ratios differ, and they do in your list above.

I have no idea why these guys here suddenly say no crop factor from FF to MF.

Who said that?

Often time on the internet people refuse to believe aperture is also affected by crop factor and it’s happening again.

1. Aperture is not affected by glassless adapters.
2. Equivalent aperture is affected by glassless adapters.

 

[Batdude]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

By any chance has anyone ever made a helpful chart or are there any out there on the internet that you like to reference to?

Like this

https://blog.kasson.com/gfx-50s/ff-equivalent-focal-lengths-of-hasselblad-xcd-fuji-gf-lenses/

but with f-stops?

Hey thanks for the link.

Please forgive my ignorance but I'm completely new at this and I'm still confused. I get that a (GFX) 23mm lens is 18mm, a (GFX) 80mm is a 62 and a (GFX) 110 is 86 FF equivalent. But I don't have any of those GFX prime lenses, so what exact focal length is my Nikkor 85mm and my Nikkor 50mm on the camera with the adapter?

Thank you sir.

 

[VoltMan]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

By any chance has anyone ever made a helpful chart or are there any out there on the internet that you like to reference to?

Like this

https://blog.kasson.com/gfx-50s/ff-equivalent-focal-lengths-of-hasselblad-xcd-fuji-gf-lenses/

but with f-stops?

Hey thanks for the link.

Please forgive my ignorance but I'm completely new at this and I'm still confused. I get that a (GFX) 23mm lens is 18mm, a (GFX) 80mm is a 62 and a (GFX) 110 is 86 FF equivalent. But I don't have any of those GFX prime lenses, so what exact focal length is my Nikkor 85mm and my Nikkor 50mm on the camera with the adapter?

Thank you sir.

How about I give you my simple example, which works for me ? Maybe it will help you too.

A Nikon 85mm 1.4 on the GFX body REMAINS an 85mm. Its original aperture of 1.4 REMAINS 1.4.

Warning I’m 5 glasses into a nice single malt.

Maybe we start with a Nikon 85 mm F1.4. And a fringer adapter. First off, it’s important to understand that the lens itself will always have an 85mm focal distance. Pragmatically the adapter won’t change that. That focal length is measured from the optical center of the lense to the surface of the sensor. Since the Nikon lens was made for a deeper DSLR body the adapter needs to add a few mm to compensate for the relative shallowness of the GFX camera body. Thus the lens is still 85mm from optical center to the surface of the sensor. Secondly, the adapter of course provides appropriate mounting rings to mechanically adapt the Nikon lens to the GFX. Of course, the adapter provides conversion of the electronic protocols.

Thus the 85mm on the GFX body REMAINS an 85mm. Its original aperture of 1.4 REMAINS 1.4.

The big thing of course that CHANGES is the lens’ field of view as the GFX sensor covers more of the image circle projected by the lens. That lens when mounted on a Nikon DSLR gives a maximum field of view (FOV) which is approximately 28°. When mounted on a GFX camera the lens provides a slightly wider field of view (FOV) of about 35°. This is where conversion factors come in handy. Note for something like field of view you can only estimate because no one measures and publishes this figure. This is where the conversion factors can be used.


Let’s stop there. I need ice. So for now can you understand that the Nikon 85 mm f1.4 is also an 85mm f1.4 on the GFX? The field of you on the GFX will be slightly wider, because it uses more of the image circle.

 

[VoltMan]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

By any chance has anyone ever made a helpful chart or are there any out there on the internet that you like to reference to?

Like this

https://blog.kasson.com/gfx-50s/ff-equivalent-focal-lengths-of-hasselblad-xcd-fuji-gf-lenses/

but with f-stops?

Hey thanks for the link.

Please forgive my ignorance but I'm completely new at this and I'm still confused. I get that a (GFX) 23mm lens is 18mm, a (GFX) 80mm is a 62 and a (GFX) 110 is 86 FF equivalent. But I don't have any of those GFX prime lenses, so what exact focal length is my Nikkor 85mm and my Nikkor 50mm on the camera with the adapter?

Thank you sir.

Part 2 - Conversion BS

OK these are my opinions by the way. First take any of these conversion factors with a grain of salt , as approximations. Simply because each lens has its own unique properties and the variables here , which are field of view, and depth of field, are not set in stone for a given focal length. As an example the max field (angle) of view on a Nikon 85mm might be 28.5°, but it is 28.6° on a Sigma Art 85mm 1.4. So even though some people like Jim publish technical tables with exact conversions, you really only need an approximation in practical usage. Also in my practical experience I don’t care to calculate FF equivalent depth of field , because if you remember an 85 mm Nikon lens is still 85 mm after adaptation to the GFX. It’s about the same depth of field as if you had a GF 85, 1.4 from Fujifilm. The one thing I find handy to calculate is the approximate field/angle of view I might get. Since DSLRs are 3:2 sensors and GFX is 4:3 that even gets whacky. However, if you find the published data for the full frame camera lens, you simply multiply by 1.25 and you’ll get approximately the field/angle of view when’s it’s mounted on your GFX. Thus the 28° on the Nikon becomes about 35° on the GFX.

But actually in reality with myself, I don’t even look at any of that anymore. I just figure out the GF focal length I want to have for the shot and get roughly the same in the FullFrame version. So to me an 85mm 1.4 is like an 80mm 1.7 or such.

Also, none of this really matters because you need to find out how the lens works on the adapter. The Nikon 85 mm supposedly has very little vignette and distortion. It should perform roughly about like a normal GF 80 mm. although a little tighter.

So just toss conversions and try the lens. BTW - your Nikkor 50mm is still 50mm on the GFX.

OK I hope this helps . Ciao.

 

[dbateman]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

By any chance has anyone ever made a helpful chart or are there any out there on the internet that you like to reference to?

Like this

https://blog.kasson.com/gfx-50s/ff-equivalent-focal-lengths-of-hasselblad-xcd-fuji-gf-lenses/

but with f-stops?

Hey thanks for the link.

Please forgive my ignorance but I'm completely new at this and I'm still confused. I get that a (GFX) 23mm lens is 18mm, a (GFX) 80mm is a 62 and a (GFX) 110 is 86 FF equivalent. But I don't have any of those GFX prime lenses, so what exact focal length is my Nikkor 85mm and my Nikkor 50mm on the camera with the adapter?

Thank you sir.

How about I give you my simple example, which works for me ? Maybe it will help you too.

A Nikon 85mm 1.4 on the GFX body REMAINS an 85mm. Its original aperture of 1.4 REMAINS 1.4.

Warning I’m 5 glasses into a nice single malt.

Maybe we start with a Nikon 85 mm F1.4. And a fringer adapter. First off, it’s important to understand that the lens itself will always have an 85mm focal distance. Pragmatically the adapter won’t change that. That focal length is measured from the optical center of the lense to the surface of the sensor. Since the Nikon lens was made for a deeper DSLR body the adapter needs to add a few mm to compensate for the relative shallowness of the GFX camera body. Thus the lens is still 85mm from optical center to the surface of the sensor. Secondly, the adapter of course provides appropriate mounting rings to mechanically adapt the Nikon lens to the GFX. Of course, the adapter provides conversion of the electronic protocols.

Thus the 85mm on the GFX body REMAINS an 85mm. Its original aperture of 1.4 REMAINS 1.4.

The big thing of course that CHANGES is the lens’ field of view as the GFX sensor covers more of the image circle projected by the lens. That lens when mounted on a Nikon DSLR gives a maximum field of view (FOV) which is approximately 28°. When mounted on a GFX camera the lens provides a slightly wider field of view (FOV) of about 35°. This is where conversion factors come in handy. Note for something like field of view you can only estimate because no one measures and publishes this figure. This is where the conversion factors can be used.

Let’s stop there. I need ice. So for now can you understand that the Nikon 85 mm f1.4 is also an 85mm f1.4 on the GFX? The field of you on the GFX will be slightly wider, because it uses more of the image circle.

Yes we have the correct answer that has lead to hundreds of millions of posts in the four thirds forums. The lens is a designed instrument that doesn't magically change. But it will have an image circle that you can cut away from or if lucky, image more of. Thats really it.

The field of view on Gfx will depend on the size of the image circle and many lenses will not project a large image circle. So you can't always assume you will get more field of view.

The same is true for depth of field. Many lenses are designed to have different fall offs or smoothness. You can't always assume you will get more or less depth of field by cropping or capturing more of that image circle. More factors are in play with depth of field.

The important thing is exposure will always be the same, regardless of crop. You will use the same shutter speed and maybe ISO value (manufacturers will use different definitions for ISO) for the same lens fixed aperture setting.

 

[Batdude]

I have a few dumb questions that I'm not sure of

So with this Fringer adapter on this medium format body with my Nikkor lenses, if I set for example the aperture to F2 (or whatever) am I getting F2 or is it a different aperture?

Thank you for your understanding.

f2 X 1.27 = approx f2.5

Wouldn't it be the other way around? F2 x .79 = 1.58 equivalent? I thought that with a larger sensor, you achieved a shallower DoF. Does that change with an adapter??

However, AFAIK, for light with a "dumb" adapter, F2 is still F2.

Take one step back, what if you mounted a f1.4 mft lens on a full frame camera? Sensor is bigger but every is times 2 = f2.8

I don't understand what you're trying to say here.

now he mounts a ff f2 lens on a bigger sensor camera, what do you think? Up or down?

If you mount a FF f/2 lens on a camera with a bigger sensor, the FF equivalent f-stop will be wider, or numerically smaller.

By any chance has anyone ever made a helpful chart or are there any out there on the internet that you like to reference to?

Like this

https://blog.kasson.com/gfx-50s/ff-equivalent-focal-lengths-of-hasselblad-xcd-fuji-gf-lenses/

but with f-stops?

Hey thanks for the link.

Please forgive my ignorance but I'm completely new at this and I'm still confused. I get that a (GFX) 23mm lens is 18mm, a (GFX) 80mm is a 62 and a (GFX) 110 is 86 FF equivalent. But I don't have any of those GFX prime lenses, so what exact focal length is my Nikkor 85mm and my Nikkor 50mm on the camera with the adapter?

Thank you sir.

How about I give you my simple example, which works for me ? Maybe it will help you too.

A Nikon 85mm 1.4 on the GFX body REMAINS an 85mm. Its original aperture of 1.4 REMAINS 1.4.

Warning I’m 5 glasses into a nice single malt.

Maybe we start with a Nikon 85 mm F1.4. And a fringer adapter. First off, it’s important to understand that the lens itself will always have an 85mm focal distance. Pragmatically the adapter won’t change that. That focal length is measured from the optical center of the lense to the surface of the sensor. Since the Nikon lens was made for a deeper DSLR body the adapter needs to add a few mm to compensate for the relative shallowness of the GFX camera body. Thus the lens is still 85mm from optical center to the surface of the sensor. Secondly, the adapter of course provides appropriate mounting rings to mechanically adapt the Nikon lens to the GFX. Of course, the adapter provides conversion of the electronic protocols.

Thus the 85mm on the GFX body REMAINS an 85mm. Its original aperture of 1.4 REMAINS 1.4.

The big thing of course that CHANGES is the lens’ field of view as the GFX sensor covers more of the image circle projected by the lens. That lens when mounted on a Nikon DSLR gives a maximum field of view (FOV) which is approximately 28°. When mounted on a GFX camera the lens provides a slightly wider field of view (FOV) of about 35°. This is where conversion factors come in handy. Note for something like field of view you can only estimate because no one measures and publishes this figure. This is where the conversion factors can be used.

Let’s stop there. I need ice. So for now can you understand that the Nikon 85 mm f1.4 is also an 85mm f1.4 on the GFX? The field of you on the GFX will be slightly wider, because it uses more of the image circle.

Yes got it thank you very much you’re awesome