Wide-Eyed

[Chris Kern]

Apparently, Fuji is about to introduce a 50mm f/1.0 lens for its crop-sensor cameras (i.e., 75mm equivalent).

I'm impressed, I guess, but curious about who actually would buy such a lens.  Assuming it's sharp wide-open (at $1500 U.S., presumably it will be), the depth-of-field is going to be exceedingly narrow at typical portrait distances.  Anybody have other ideas what other applications would be useful?

[shadowblade]

It will be equivalent in angle of view and depth of field to a 75/1.5 lens - not particularly unusual.

[Chris Kern]

It will be equivalent in angle of view and depth of field to a 75/1.5 lens - not particularly unusual.

But is it common to shoot portraits at that wide an aperture?  Assuming you nailed focus on the nearest eye, wouldn't the rest of the face be awfully soft?  And if not portraits, what?  I can't see shooting at 50mm f/1.0 (or 75mm f/1.5 equivalent) on the street at night, but maybe I'm missing something.

[Slobodan Blagojevic]

One word: Rembrandt.

[Chris Kern]

One word: Rembrandt.

Well, I'm flattered.  But while I'm certainly old, I hesitate to call myself a master.

[Eric Myrvaagnes]

I don't think Rembrandt used a Fuji.   

[Slobodan Blagojevic]

Well, I'm flattered.  But while I'm certainly old, I hesitate to call myself a master.

Haha, Chris, I am sure you are a master in your own right, but I had something else in mind (sorry I didn't explain what I had in mind earlier, I thought I lot of people know it - plus I couldn't find the article I remembered seeing some time ago):

Rembrandt used that technique in his paintings, where one, closer eye, is sharp, in focus, while the other eye and other parts of the face on that side are slightly blurred.

Here is the closest article I could find today:

https://phys.org/news/2010-05-decodes-rembrandt-magic.html

[Chris Kern]

Rembrandt used that technique in his paintings, where one, closer eye, is sharp, in focus, while the other eye and other parts of the face on that side are slightly blurred.

I take your point.  But everyone knows how primitive autofocus systems were in that era.  Autoexposure was dodgy, too: notice how dark many of Rembrandt's portraits are.

[shadowblade]

But is it common to shoot portraits at that wide an aperture?  Assuming you nailed focus on the nearest eye, wouldn't the rest of the face be awfully soft?  And if not portraits, what?  I can't see shooting at 50mm f/1.0 (or 75mm f/1.5 equivalent) on the street at night, but maybe I'm missing something.

Head-and-shoulders? Probably not. But definitely for three-quarters and full-length portraits. For longer portraits, you can shoot wide open and still have the whole body in focus.

[Slobodan Blagojevic]

But is it common to shoot portraits at that wide an aperture?  Assuming you nailed focus on the nearest eye, wouldn't the rest of the face be awfully soft?...

Well, it will be soft. But is that really unacceptable? This is a result of 135/2.0 (trying to match the age of the Rembrandt model  )

[Chris Kern]

Well, it will be soft. But is that really unacceptable? This is a result of 135/2.0 (trying to match the age of the Rembrandt model  )

Yes, that works well.  I've used the same selective-focus technique for that kind of shot: tightly-framed candid portrait, three-quarters profile:



But my initial question wasn't whether it would be possible to find any application for a 50mm f/1.0 lens on a crop-sensor camera, but rather who would have sufficient use for one to be willing to spend $1500 U.S. for it.  And it was a real question, not a rhetorical criticism of Fuji's decision to offer the product.  Presumably they didn't design it for the apocryphal dentist with a closet full of unused Leica gear.  My brother used to work for Fujifilm and they don't think that way.

Again, assuming the lens is optically good enough to be used wide open—and at that price, it ought to be—the two applications that immediately came to mind were portraiture and low-light shooting (e.g., streets at night).  But it strikes me as a suboptimal aperture and focal length, respectively, for those two applications.  At normal portrait distances, I think f/1.0 is going to be too shallow for most subjects.  And for most low-light situations, at least in my experience, a shorter focal length (34mm or 23mm on a crop sensor) is almost always a better choice.

So what else am I missing?  Other than the Rembrandt effect?

[David Sutton]

We assume that a lens like that would be bought to use wide open, so I'd look to advantages in bokeh, sharpness, auto focus, weather sealing and use in low light compared to the other options.

It will be equivalent in angle of view and depth of field to a 75/1.5 lens - not particularly unusual.

Yes and no. The depth of field and f number don't change with crop factor. But the photographer to subject distance may.

[shadowblade]

We assume that a lens like that would be bought to use wide open, so I'd look to advantages in bokeh, sharpness, auto focus, weather sealing and use in low light compared to the other options.
Yes and no. The depth of field and f number don't change with crop factor. But the photographer to subject distance may.

With the same subject framing, the depth of field certainly changes.

A 75mm lens on a full-frame camera will frame a subject identically, and at the same distance, to a 50mm lens on a 1.5x crop body.

At identical framing and focus distance, with an acceptable circle of confusion scaled to the same percentage of the frame (say, 0.03 for full-frame and 0.02 for the crop), the depth of field of a f/1.0 lens on the crop will be the same as that of an f/1.5 lens on the full frame.

I can show the maths that proves it, but can't type and copy equations on my phone.

[David Sutton]

With the same subject framing, the depth of field certainly changes.

A 75mm lens on a full-frame camera will frame a subject identically, and at the same distance, to a 50mm lens on a 1.5x crop body.

At identical framing and focus distance, with an acceptable circle of confusion scaled to the same percentage of the frame (say, 0.03 for full-frame and 0.02 for the crop), the depth of field of a f/1.0 lens on the crop will be the same as that of an f/1.5 lens on the full frame.

I can show the maths that proves it, but can't type and copy equations on my phone.

Yep. Not expressing myself well.
Its not so much the sensor size as such, but rather the larger the sensor the closer the photographer may probably get, all things being equal. With the concomitant advantages (small DoF) and disadvantages (ditto).

[shadowblade]

Yep. Not expressing myself well.
Its not so much the sensor size as such, but rather the larger the sensor the closer the photographer may probably get, all things being equal. With the concomitant advantages (small DoF) and disadvantages (ditto).

With a larger sensor, you don't move closer. That changes the composition. Instead, you need a longer focal length, but shoot from the same position.

For the same composition from the same position as a 50mm on 1.5x crop, you need a 75mm lens on full-frame. When shooting from the same position, 75mm f/1.5 on full-frame will give you the same DOF as 50mm f/1.0 on 1.5x crop.

[David Sutton]

We're really talking about different things.
I don't have those lenses so I crop, stitch or move. Yes the composition changes. But this is more interesting for the photographer.
If I use a 100mm lens at f 2.8 on an APS-C and need 6 images for a stitch, have I achieved the medium format “look”?
Whatever, the "look" is something not achievable with a single shot from a full frame or crop sensor.
Same with cropping or moving. A photographer doesn't think about what an equivalent would be on some other system, he/she works with the limitations of what is at hand.

[Manoli]

from the archive,
critical focus / DOF
shot on FF 75/f2, lightly cropped,

[KLaban]

from the archive,
critical focus / DOF
shot on FF 75/f2, lightly cropped,

Manoli, simply beautiful: literally.

[Chris Kern]

from the archive

Very nice.

[Petrus]

What I am wondering is why did Fujinon make a 50mm f/1 lens, when they already have 56mm f/1.2 which is practically the same, and a great portrait lens.

What comes to usefulness of having a super fast lens it really never hurts, except the neck and the wallet.

When I was still working I often used the Sigma Art 50mm f/1.4 wide open for facial portraits. Either for some caricature effect (for cabinet ministers and PM...) or for nice soft focus effect, like in the attached sample. If you wonder about the funny hat, that is the high school graduation head gear traditionally used in Scandinavia.

Nikon D800e, Sigma Art 50mm at f/1.4 1/3200 sec.