Reading mode: Light Dark

Will we ever see the Focal mm in the EVF

Go to last post
Joel Klein

Joel Klein

Senior Member
Messages
1,337
Solutions
1
Reaction score
935
Location
US
Good morning.

Using the 24-70 - 70-200 so much, I want the EVF to show/update live the Focal mm. So when I want a 50mm shot, I want it to be 50mm, not 48 or 51... etc...

Since the lens communicates with the camera, then why can't we see the Focal mm live? I know I can press the button on the lens to show it, but that's not helpful while having the eye in the EVF.

Am I the only one missing it?

Joel
 
I posted a similar question regarding focus distance (where, as far as I know, it isn’t even displayed — precisely — on lenses which have a display).

I guess adding such options (ie. the option to have focal length or distance displayed wherever) to the setup menus might make the menus more and more complicated, and they’re things that fewer and fewer people are interested in.
 
Since that data is recorded in the image file theoretically it could be updated in real time and displayed in the EVF, if that capability exists in the lens firmware. Revising the display software to include that data is doable.

Not sure why it would matter in real time, one can preset the zoom ring on the lens and should know if one is at either end of the zoom range or in the middle, but why not?

Going further, since a dSLR is but a computer dedicated to image acquisition why not have readouts about core use/temps/speed and anything else imaginable? How that would improve picture taking I don't know but it spins the propeller on my beanie.
 
I don't know about anything being too complicated these days... I've had to chimp my images a few times to compare and test my zooms. I'd also like the focus confirmation indicator at the center instead of way off in the corner. I don't want all items at the top, but a few key ones I chose would be nice. On the Z50 it is in the field of view instead of the letterbox as well.

It would be nice to toggle features on and off. It should be easy as it is just software once you have the EVF. I could easily envision having an app that let you fully configure your firmware.

Maybe even voice control through Snap Bridge: "Nikon set focal length to 50 user mode 3."

--

SkyRunR
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
'Out of the darkness there must come out the light.' Bob Marley
 
Joel Klein said:
Good morning.

Using the 24-70 - 70-200 so much, I want the EVF to show/update live the Focal mm. So when I want a 50mm shot, I want it to be 50mm, not 48 or 51... etc...

Since the lens communicates with the camera, then why can't we see the Focal mm live? I know I can press the button on the lens to show it, but that's not helpful while having the eye in the EVF.

Am I the only one missing it?

Joel
Click to expand...
It's worth noting that the marketed focal lengths of lenses are rounded to the nearest "nice" value, and even if a lens is actually 50mm, it's only 50mm at infinity focus.

I too would like to see focal length pop up in the viewfinder when zooming (my panasonic S5 does this, it's nice), but I'd suggest not sweating the details. There's no real-world difference between 48, 50, and 51. A 50mm lens might actually have a true focal length measured at 48mm anyway.

https://photo.stackexchange.com/questions/91601/are-lenses-marked-with-the-true-focal-length

I swear I've seen "true" or "measured" focal lengths provided in some lens reviews, but I can't find them now. Sorry!

I do recall one iteration of the nikon 70-200/2.8G was notorious for losing focal length at close focus distances. I think the long end was closer to 140mm if focused at a head-and-shoulders portrait distance, for example.
 
Last edited:
I don't need the focal length in the viewfinder. It is already crowded enough there.

I just zoom to fit my subject in the picture. Or achieve a certain composition. Or do the walking zoom.

If I forgot what lens I mounted, I can look on the barrel.

Next thing is, we need the DoF, which nowadays is omitted from the barrel, that is something I used frequently.
 
Last edited:
Boudewijn van der Drift said:
I don't need the focal length in the viewfinder. It is already crowded enough there.

I just zoom to fit my subject in the picture. Or achieve a certain composition. Or do the walking zoom.

If I forgot what lens I mounted, I can look on the barrel.

Next thing is, we need the DoF, which nowadays is omitted from the barrel, that is something I used frequently.
Click to expand...
That is the reason for a menu option to customize what shows in the EVF.

Some shoot with AF-C Release, and some with AF-C Focus priority.

When I sort pictures, sorting by Focal length makes it easy. However, if the focal ranges are not precise, it makes quick sorting impossible.
 
Never missed not having that feature after 30 years of using zoom lenses.

I could say sure why not have it. But as has already been mentioned, it won’t be accurate to the degree you seem to want it. 50mm, not 49 or 51? Really? Focal length often changes with focus distance.

I know roughly where I am. That’s good enough. I’m worrying about composition, not my precise focal length.
 
I can understand it might be a feature people may want. But given Focal length can actually change at different focal lengths and is therefore never going to be accurate why do you want to know this information in real time. Surely the composition is the key not the focal length. I'd just like to understand why you may wish to use this information in real time photography.

--
Please don't quote long posts, it just fills up the forum with repetitive information. Just replying to the poster or selectively quoting will make it all easier to read.
 
Last edited:
romfordbluenose said:
I can understand it might be a feature people may want. But given Focal length can actually change at different focal lengths and is therefore never going to be accurate why do you want to know this information in real time. Surely the composition is the key not the focal length. I'd just like to understand why you may wish to use this information in real time photography.
Click to expand...
 
Brian Kimball said:
Joel Klein said:
Good morning.

Using the 24-70 - 70-200 so much, I want the EVF to show/update live the Focal mm. So when I want a 50mm shot, I want it to be 50mm, not 48 or 51... etc...

Since the lens communicates with the camera, then why can't we see the Focal mm live? I know I can press the button on the lens to show it, but that's not helpful while having the eye in the EVF.

Am I the only one missing it?

Joel
Click to expand...
It's worth noting that the marketed focal lengths of lenses are rounded to the nearest "nice" value, and even if a lens is actually 50mm, it's only 50mm at infinity focus.

I too would like to see focal length pop up in the viewfinder when zooming (my panasonic S5 does this, it's nice), but I'd suggest not sweating the details. There's no real-world difference between 48, 50, and 51. A 50mm lens might actually have a true focal length measured at 48mm anyway.

https://photo.stackexchange.com/questions/91601/are-lenses-marked-with-the-true-focal-length

I swear I've seen "true" or "measured" focal lengths provided in some lens reviews, but I can't find them now. Sorry!

I do recall one iteration of the nikon 70-200/2.8G was notorious for losing focal length at close focus distances. I think the long end was closer to 140mm if focused at a head-and-shoulders portrait distance, for example.
Click to expand...
Right.

For example, many 50mm lenses are designed as 51.6mm

You can get some specific information on various lenses at the PhotonsToPhotos Optical Bench Hub

For example, the Original Poster (OP) has the Nikon Nikkor Z 70-200mm f/2.8 VR S

[ATTACH alt="Best viewed "original size" "]3109681[/ATTACH]
Best viewed "original size"

Note that at infinity focus 200mm is actually 196mm
If you focus closer that drops to 133mm (!) or so.

Because of distortion, focal length is a poor proxy for angle of view so a display of angle of view would be better.

In any case, despite the OP desiring this feature, it's hard for me to see how it would really impact ones photography. The beauty of a through-the-lens system is that the photographer doesn't need this information to compose their image.

Regards



--
Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )
 

Attachments

  • 264a3efb8e8d4fe1a5d36e72abf40d9d.jpg.png
    264a3efb8e8d4fe1a5d36e72abf40d9d.jpg.png
    168.5 KB · Views: 0
Joel Klein said:
Good morning.

Using the 24-70 - 70-200 so much, I want the EVF to show/update live the Focal mm. So when I want a 50mm shot, I want it to be 50mm, not 48 or 51... etc...

Since the lens communicates with the camera, then why can't we see the Focal mm live? I know I can press the button on the lens to show it, but that's not helpful while having the eye in the EVF.

Am I the only one missing it?

Joel
Click to expand...
I'm of the opinion that for 99.999% of still photographers, I have real doubts that it would be worth bothering about.

But for the hundreds in that 0.001 percentile, who see value in using stated focal length values of zoom lenses designed primarily for still photography in an attempt to exactly match framing between cameras, I can see how that might have value.

--

Ellis Vener
A working photographer since 1984.
To see my work, please visit http://www.ellisvener.com
Or on Instagram @EllisVenerStudio
 
bclaff said:
Brian Kimball said:
Joel Klein said:
Good morning.

Using the 24-70 - 70-200 so much, I want the EVF to show/update live the Focal mm. So when I want a 50mm shot, I want it to be 50mm, not 48 or 51... etc...

Since the lens communicates with the camera, then why can't we see the Focal mm live? I know I can press the button on the lens to show it, but that's not helpful while having the eye in the EVF.

Am I the only one missing it?

Joel
Click to expand...
It's worth noting that the marketed focal lengths of lenses are rounded to the nearest "nice" value, and even if a lens is actually 50mm, it's only 50mm at infinity focus.

I too would like to see focal length pop up in the viewfinder when zooming (my panasonic S5 does this, it's nice), but I'd suggest not sweating the details. There's no real-world difference between 48, 50, and 51. A 50mm lens might actually have a true focal length measured at 48mm anyway.

https://photo.stackexchange.com/questions/91601/are-lenses-marked-with-the-true-focal-length

I swear I've seen "true" or "measured" focal lengths provided in some lens reviews, but I can't find them now. Sorry!

I do recall one iteration of the nikon 70-200/2.8G was notorious for losing focal length at close focus distances. I think the long end was closer to 140mm if focused at a head-and-shoulders portrait distance, for example.
Click to expand...
Right.

For example, many 50mm lenses are designed as 51.6mm

You can get some specific information on various lenses at the PhotonsToPhotos Optical Bench Hub

For example, the Original Poster (OP) has the Nikon Nikkor Z 70-200mm f/2.8 VR S

Best viewed "original size"
Best viewed "original size"

Note that at infinity focus 200mm is actually 196mm
If you focus closer that drops to 133mm (!) or so.

Because of distortion, focal length is a poor proxy for angle of view so a display of angle of view would be better.

In any case, despite the OP desiring this feature, it's hard for me to see how it would really impact ones photography. The beauty of a through-the-lens system is that the photographer doesn't need this information to compose their image.

Regards

--
Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )
Click to expand...
Focusing closer it’s only 133???😲 How is it possible not see the lens breathing???
 
Joel Klein said:
bclaff said:
Note that at infinity focus 200mm is actually 196mm
If you focus closer that drops to 133mm (!) or so.
Click to expand...
Focusing closer it’s only 133???😲 How is it possible not see the lens breathing???
Click to expand...
You confusing dropping focal length with focus breathing.
It's actually not possible for a lens to maintain focal length and not focus breath.

This lens does not focus breath.
Angle of view at infinity is 12.27 degrees and at close focus essentially identical at 12.21 degrees.
 
bclaff said:
Joel Klein said:
bclaff said:
Note that at infinity focus 200mm is actually 196mm
If you focus closer that drops to 133mm (!) or so.
Click to expand...
Focusing closer it’s only 133???😲 How is it possible not see the lens breathing???
Click to expand...
You confusing dropping focal length with focus breathing.
It's actually not possible for a lens to maintain focal length and not focus breath.

This lens does not focus breath.
Angle of view at infinity is 12.27 degrees and at close focus essentially identical at 12.21 degrees.
Click to expand...
 
Joel Klein said:
bclaff said:
Joel Klein said:
bclaff said:
Note that at infinity focus 200mm is actually 196mm
If you focus closer that drops to 133mm (!) or so.
Click to expand...
Focusing closer it’s only 133???😲 How is it possible not see the lens breathing???
Click to expand...
You confusing dropping focal length with focus breathing.
It's actually not possible for a lens to maintain focal length and not focus breath.

This lens does not focus breath.
Angle of view at infinity is 12.27 degrees and at close focus essentially identical at 12.21 degrees.
Click to expand...
So the.27 to .21 is the same difference from 200mm to 133?
Click to expand...
Focusing from infinity to nearby at the 200mm setting goes from 196mm to 133mm real focal length but angle of view is essentially unchanged going from 12.27 degrees to 12.21 degrees (0.06 degrees is probably much lower than the accuracy of the ray tracing.)
 
Joel Klein said:
Good morning.

Using the 24-70 - 70-200 so much, I want the EVF to show/update live the Focal mm. So when I want a 50mm shot, I want it to be 50mm, not 48 or 51... etc...

Since the lens communicates with the camera, then why can't we see the Focal mm live? I know I can press the button on the lens to show it, but that's not helpful while having the eye in the EVF.

Am I the only one missing it?

Joel
Click to expand...
Even though I started out using fixed FL decades ago, I am now a mostly zoom user. So, I like to see the FL I am using. However, I don't care if the number reported is 48 or 51; it is not that important. Besides, the FL on a lens is really a round-up or round-down approximation and it is straightly true only at infinity.
 
bclaff said:
Joel Klein said:
bclaff said:
Joel Klein said:
bclaff said:
Note that at infinity focus 200mm is actually 196mm
If you focus closer that drops to 133mm (!) or so.
Click to expand...
Focusing closer it’s only 133???😲 How is it possible not see the lens breathing???
Click to expand...
You confusing dropping focal length with focus breathing.
It's actually not possible for a lens to maintain focal length and not focus breath.

This lens does not focus breath.
Angle of view at infinity is 12.27 degrees and at close focus essentially identical at 12.21 degrees.
Click to expand...
So the.27 to .21 is the same difference from 200mm to 133?
Click to expand...
Focusing from infinity to nearby at the 200mm setting goes from 196mm to 133mm real focal length but angle of view is essentially unchanged going from 12.27 degrees to 12.21 degrees (0.06 degrees is probably much lower than the accuracy of the ray tracing.)
Click to expand...
I'm having more and more questions now. I need a crash course in this matter. How the Focal length essentially zooms/makes the subject bigger and compressed and could be at 135mm or 200mm and produce the same subject framing.
 
Joel Klein said:
bclaff said:
Joel Klein said:
bclaff said:
Joel Klein said:
bclaff said:
Note that at infinity focus 200mm is actually 196mm
If you focus closer that drops to 133mm (!) or so.
Click to expand...
Focusing closer it’s only 133???😲 How is it possible not see the lens breathing???
Click to expand...
You confusing dropping focal length with focus breathing.
It's actually not possible for a lens to maintain focal length and not focus breath.

This lens does not focus breath.
Angle of view at infinity is 12.27 degrees and at close focus essentially identical at 12.21 degrees.
Click to expand...
So the.27 to .21 is the same difference from 200mm to 133?
Click to expand...
Focusing from infinity to nearby at the 200mm setting goes from 196mm to 133mm real focal length but angle of view is essentially unchanged going from 12.27 degrees to 12.21 degrees (0.06 degrees is probably much lower than the accuracy of the ray tracing.)
Click to expand...
I'm having more and more questions now. I need a crash course in this matter. How the Focal length essentially zooms/makes the subject bigger and compressed and could be at 135mm or 200mm and produce the same subject framing.
Click to expand...
Returning to the PhotonsToPhotos Optical Bench and the Nikon Nikkor Z 70-200mm f/2.8 VR S you could click on the Optics Primer button and see what you can learn from the primer.

As you focus closer than infinity magnification increases (it's zero at infinity).
I assume by subject you mean the thing that is in focus.
I assume by framing you mean angle of view.
But I'm unsure what thing(s) you are confused about.

Remember, focus breathing is an apparent change in size when you don't move the camera but do change the focus. Breathing happens if the angle of view changes with focus.
 
Focal length of general purpose lenses is always measured at 1:infinity reproduction ratio.
 
You must log in or register to reply here.

Similar threads

N
Already have a 70-200... 24-70 or 24-120?
2 3
Replies
48
Views
6K
buildingsights
B
H
Shots are not sharp when shooting at a long focal length with the NIKKOR Z 100-400mm f/4.5-5.6 VR S
3 4 5
Replies
81
Views
4K
ajr images
A
Smaug01
  • Poll Poll
35 mm Z NiKKOR: 35/1.4 vs. 35/1.8 S, vs. 28/2.8
2 3
Replies
44
Views
2K
Rich Rosen
R
Bird_Nerd
Updated ZR Pre-Release Specs
Replies
1
Views
230
Z8ZF
Z8ZF
B
Preliminary Evaluation of the Megadap ETZ21 Pro+ with Sony Lenses on the Z8: Stabilization
Replies
7
Views
356
circa2000
C

Keyboard shortcuts

f
Forum
m
My threads
Mobile site
About
Editorial content
Cameras & Lenses
Community
All content, design, and layout are Copyright © 1998–2025 Digital Photography Review All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
When you use DPReview links to buy products, the site may earn a commission.
©GPS Media - Guides, Products, Services.
Back
Top