Fuji 23 1.4 WR as ‘35-50mm’ zoom

GMacF wrote:

I DID do some testing so hopefully this clears things up:

Below is a shot taken @23mm with the 1.4 digital teleconverter on (so approx 35mm equiv):

and one taken at 35mm:

This is slightly pedantic but I’m guessing someone will point out that the cropped 23mm shot has a wider field of view 🙂  23x1.4 is more like 32.

But I’m glad someone demonstrated the principle visually.

Jeff Biscuits wrote:

GMacF wrote:

I DID do some testing so hopefully this clears things up:

Below is a shot taken @23mm with the 1.4 digital teleconverter on (so approx 35mm equiv):

and one taken at 35mm:

This is slightly pedantic but I’m guessing someone will point out that the cropped 23mm shot has a wider field of view 🙂 23x1.4 is more like 32.

But I’m glad someone demonstrated the principle visually.

That DID occur to me - I actually held back a little at around 33mm if you look at the EXIF but this wasn't purely by design. I've found it's quite difficult to nail the focal lengths bang on 

Additionally, my examples should also help the OP with their initial query - as I originally stated, on a global level there really isn't much difference between native and using a crop mode (by whatever means).

emirco wrote:

Let me google it for you

Google all the incorrect information you like 🙂 A far perspective produces background compression. It’s just that if you have a far perspective with a wide angle lens, you’re going to have to crop so much to create an image of only the distant elements that you’ll struggle to print a postage stamp, so people tend not to do it. But a wide angle lens will give you exactly the same compression as a telephoto if you stand in the same place to use both.

Take a compact camera as an example. The Lumix TZ90 has a whopping 720mm-equivalent telephoto lens. But it’s only actually 129mm, which would be a portrait lens on 35mm film. The reason why it gives such a telephoto view is that it’s only using a small area of projected image. (Of course, small sensors pack their pixels more densely than large sensors, so you end up with similar resolution when you use a sensor designed to only use a small area.)

This is exactly the same as cropping: you use a smaller area of projected image, and the result is the same as using a longer lens with the same size of aperture (but with the longer lens, that same aperture would have a smaller f-number, because f is the focal length).

BeatX wrote:

Hmmm, interestint point. I didn't thought about it this way. I need to run some tests to confirm Your words, unfortunately I don't have access to any lenses than those two I have listed in my signature. But I will keep in mind to check it in the future, when there will be opportunity. Thanks

Your current lenses are fine for the test. Stand in one place, point at the same spot, and take one photo with each lens.

Then crop the 23mm image so that its width is roughly 0.7x its original value.

You should see that the location of every part of the image is the same.

For a bonus test, take the 23mm image at f/2 and the 33mm image at f/2.8. You should see that the depth of field is the same in both images.

If all else fails, consider that light travels in a straight line and then imagine straight lines emanating from your eyeball/camera to everything you can see. Then make a rectangle with your thumbs and index fingers at right-angles to each other and hold it in front of you. Move that rectangle from close to your face to far away while keeping it the same size and keeping your feet in the same place… you still see the exact same view, you just see more or less of it within that rectangle depending on how narrow a field of view you restrict yourself to.

In case the point about compression needs illustrating:

Here are two shots of the horizon, both taken from Snowdon on the same day (though unfortunately pointing in different directions). One was shot at 230mm, one was shot at 10mm. The latter has been cropped, and the former has been downsized to the same resolution.

It should be clear that “compression” is not a product of focal length, only of perspective.

GMacF wrote:

Zinch wrote:

emirco wrote:

Let me google it for you

That answer is wrong. As said before, cropping IS the same as using another focal length when you consider perspective (it affects other things I listed: resolution, DoF, DR and noise to signal ratio)

Yes quite right. As Jeff pointed out on my initial reply, perspective does NOT change when just cropping. I admit my wording was off when what I meant was perspective changes when framing (and re-framing) at different focal lengths.

I DID do some testing so hopefully this clears things up:

Below is a shot taken @23mm with the 1.4 digital teleconverter on (so approx 35mm equiv):

and one taken at 35mm:

To further demonstrate below are two shots, one taken @16mm (with 2x crop) and one taken @35mm - both images have same perspective but different DOF, noise etc:

Conversely, the point I was making initially (and what others I believe are making) is the change in perspective when re-framing a shot. Below is a shot taken @23mm then re-taken @35mm but reframed so the subject (lens hood) is approx the same size:

Allright, You just saved me a lot of time and effort to perform similar test - thank You!
Seems like all clear to me, beside effect of  background "compression".
Maybe its just lack of my imagination, but Its hard for me to belive, that images taken from XF 90 and Laowa 9/2.9 (cropped to match XF 90 perspective) will have same background compression.

Andrewcn wrote:

I’m thinking of buying the 23 1.4 WR to cover the focal lengths 35, 40 and 50mm. I would make to of the sports finder mode and the1.4 digital crop.

Are there any downsides to this? I only print up to A3 and so the loss of resolution shouldn’t matter.

90% of what I shoot is in this focal range and it seems a good, lightweight, one lens coption.

Comments please.

Actually there is not a lot of difference between a  35 mm and a 50 mm lenses. They are close.   They are almost too close to carry both.  As far as FOV when not at "infinity" they are only a few steps. That is why many fixed lens cameras, e.g., the F100V,  use a 35 mm lens - it is a good compromise for a fixed lens camera.  I personally find the 35 a somewhat boring focal length and only have one for when I am limited in movement, my 50 is too long and my 28 is too short.

Some people love the 35 and consider it the Goldilocks focal length.  If you primarily shoot in the 35 to 50 range then your approach would work just fine.  It allow you to simplify your "messing with the camera" and allow you to focus more on your subject and the story you want to tell.  If you have freedom of movement - a few steps either direction will serve you well.  I seriously doubt that will many will notice any slight difference in perspective and in reality perspective is as much a matter of distance to the subject as focal length.

It does not cost anything to find out and if you fine you would like to add a different lens later then you can do so.  Leica has a digital crop mode for its Q2/Q2M.  With their 47 MP sensor that is plenty of resolution to crop - especially in the monochrome camera.  The Jpegs respect the crop and the metering respects the crop - I don't know about Fuji.  I don't know which Fuji camera you are using. However, the 26 MP sensor is more than enough to support this approach.  The 40 MP is overkill for it in terms of pure resolution, but the 40 has some other advantages for this approach.

Try it and see how it works.

Jeff Biscuits wrote:

BeatX wrote:

Hmmm, interestint point. I didn't thought about it this way. I need to run some tests to confirm Your words, unfortunately I don't have access to any lenses than those two I have listed in my signature. But I will keep in mind to check it in the future, when there will be opportunity. Thanks

Your current lenses are fine for the test. Stand in one place, point at the same spot, and take one photo with each lens.

Then crop the 23mm image so that its width is roughly 0.7x its original value.

You should see that the location of every part of the image is the same.

For a bonus test, take the 23mm image at f/2 and the 33mm image at f/2.8. You should see that the depth of field is the same in both images.

If all else fails, consider that light travels in a straight line and then imagine straight lines emanating from your eyeball/camera to everything you can see. Then make a rectangle with your thumbs and index fingers at right-angles to each other and hold it in front of you. Move that rectangle from close to your face to far away while keeping it the same size and keeping your feet in the same place… you still see the exact same view, you just see more or less of it within that rectangle depending on how narrow a field of view you restrict yourself to.

Exactly - perspective is yet another property that has been confused by this nonsense of "equivalence" between different sensor sizes that has caused more confusion than clarity.

Photography is a process of projecting a sector of 3 dimensional space on to a plane - what we mathematicians call a projective transform. All the point on a ray from the projection point are mapped to the same point on the plane. A projective transform does not respect distance. However, it respects relative distance between points as they are mapped onto the plane. The key factor is the distance from the projection point and the plane. For a camera that translates to the distance of the camera to the focal plane.

https://courses.engr.illinois.edu/cs543/sp2011/lectures/Lecture%2002%20-%20Projective%20Geometry%20and%20Camera%20Models%20-%20Vision_Spring2011.pdf