[VisualDarkness]

The point was that the "normal" lens gave a view and perspective roughly the same as the human eye - the camera saw what your eyes saw. For an APSC camera, the "nifty fifty" becomes equivalent to a not-so-nifty 75 mm.

Here is a really interesting article about eyes vs lenses that show why it's difficult to make a real comparison like that.

[stevebrot]

Here is a really interesting article about eyes vs lenses that show why it's difficult to make a real comparison like that.

Hmmm...no link? Is the PF censor at work again?*

As for the eye vs. lens discussion (to derail this thread)...that is difficult. With a 1:1 viewfinder and a 50mm lens, the magnification is about the same as the human eye. The FOV relative to the "perceptual crop" (my new and wonderful term), varies between people. For example, normal to me is a fairly broad view and even on 35mm film a 50mm lens is a bit constricting.


Steve

* I had a disappearing link (to luminous-landscape.com) on one of my posts a week or so ago.

[OregonJim]

The FOV relative to the "perceptual crop" (my new and wonderful term), varies between people.

I have heard that the human eye has a FOV of 22mm (135 relative), but as you say, the perceptual crop varies. It's (usually) closer to 40mm than 50mm.

[stevebrot]

I have heard that the human eye has a FOV of 22mm (135 relative), but as you say, the perceptual crop varies.

The full FOV (both eyes) is a little over 180 degrees, literally fish-eye territory and the projection is not strictly rectilinear though the retina is, of course, not exactly flat either


Steve

[boriscleto]

50mm became the 'normal' lens because Oskar Barnack needed a lens that could produce an enlargement from a 36x24 negative without distortions. He chose a lens based on the Cooke triplet of 1893. This became the Leitz Anastigmat 50mm/3.5.

[filoxophy]

I've by no means owned a comprehensive selection of 50s, but I like the DA50/1.8. $180 currently at B&H with warranty, excellent IQ, modern coatings, AF, etc. The build quality is admittedly budget-level, but it is light and it works. The focus ring has decent damping and a nice 180° turn for MF. A hood is optional, IMHO. The front element is recessed except at close distances. It is not internal focus, but the overall length of the lens doesn't change.

Downsides? Aforementioned plastic build, no distance/DOF scale, and inexplicable 52mm front thread.

[VisualDarkness]

Hmmm...no link? Is the PF censor at work again?*

As for the eye vs. lens discussion (to derail this thread)...that is difficult. With a 1:1 viewfinder and a 50mm lens, the magnification is about the same as the human eye. The FOV relative to the "perceptual crop" (my new and wonderful term), varies between people. For example, normal to me is a fairly broad view and even on 35mm film a 50mm lens is a bit constricting.


Steve

* I had a disappearing link (to luminous-landscape.com) on one of my posts a week or so ago.

Strange, but here it is: Cameras vs. The Human Eye

[ivanvernon]

My nifty 55 mm lens is the Canon FD 55 mm f 1.2 machined down and equipped with K mount. Manual focus and operates like Pentax M lens, meaning you can use Av mode. Less nifty is my Canon FL 55 mm f 1.2, less nifty because it must be focussed open and then manually stopped down to desired aperture.

[abmj]

My nifty 55 mm lens is the Canon FD 55 mm f 1.2 machined down and equipped with K mount. ...

I had that lens back in the day and LOVED it. I didn't think about adapting it for the K mount - didn't even know it could be done. <sigh>

[ivanvernon]

I had that lens back in the day and LOVED it. I didn't think about adapting it for the K mount - didn't even know it could be done. <sigh>

Some might question the cost: About $200 for the lens and about $300 for the conversion, but then you have an M type lens that surpasses any other fifty I have used except for the D FA 50 mm f 2.8 macro, which is not really a substitute because of the f 1.2 aperture of the Canon lens. My dream, which at the moment I cannot afford, is to do the same with the Canon 55 mm f 1.2 aspherical--the one with the special radioactive glass. That lens is tack sharp from top to bottom, and side to side, and corner to corner! However aspherical lens in FD mount goes for between $1,000 and $1,600 plus another $300 for the conversion. Yes, the nifty fifties are quite addictive, and I love the 55s for the extra reach that puts them as equivalent to 82.5 mm in full frame, and they are therefore a real great focal length for a portrait lens.

[ivanvernon]

Here are couple shots with my Chinon (Auto Revuenon) 50 mm f 1.4 and the Pentax K-7, handheld outside in light rain.

[mikeSF]

i'm all tangled up in your word "best" because there are plenty of cheap 50's out there and some really excel at one thing but may lack elsewhere.
a few in my bag include:

SMC M 50/1.7 - less than $50, very sharp for detail shooting. bokeh is average

Super Tak & SMC 55/1.4 - nice bokeh but contrast and color lacks, as does overal sharpness vs the SMC M50. some versions have yellowing.

Helios 44-2 - cheap cheap. stylish bokeh effect but just not very sharp and may wobble on the mount depending on your adapter. grease becomes crystallized over time

Helios 44M-7 - my favorite balance of super sharp IQ and great contrast with reasonable bokeh. well built all metal. decent price. hard to find

Cosina 58/1.2 - gorgeous bokeh (beats everything i've ever used hands down). decent stopped down too. expensive.

DA*55/1.4 - great sharpness, great bokeh, AF, but too expensive

[stevebrot]

Strange, but here it is: Cameras vs. The Human Eye

The linked article states a range of 40-60 degrees working FOV. The classic SLR "normal" lens (50mm, 55mm, or 58mm) is at the narrow end of the range with a 50mm lens providing about 40 degree horizontal FOV on 35mm film. On the other end, 60 degrees horizontal FOV would be attained with a 31mm lens.

The Barnack legend (above) is sounding more and more plausible all the time. He did choose the focal length, though why is not clear. It was not for lack of available choices. After all, Leica was an optics company first.


Steve

[VisualDarkness]

The linked article states a range of 40-60 degrees working FOV. The classic SLR "normal" lens (50mm, 55mm, or 58mm) is at the narrow end of the range with a 50mm lens providing about 40 degree horizontal FOV on 35mm film. On the other end, 60 degrees horizontal FOV would be attained with a 31mm lens.

The Barnack legend (above) is sounding more and more plausible all the time. He did choose the focal length, though why is not clear. It was not for lack of available choices. After all, Leica was an optics company first.


Steve

One part of it is probably that it "looked normal", a viewer found the number of points of interest with the lens rather reasonable. But to say that it is what the eyes see is a tough one since it's far from the truth. To copy what the eyes see at one moment we would need a fisheye that is extremely unsharp at the borders an with fading colors away from sensors, the 50mm is basically equivalent to a crop of the central area.

What the brain sees is even harder to make a statement about since the brain essentially merges and stitches images in rapid fashion depending on what is being viewed. Therefore in one way we can see way wider than the 40 degrees making wider lenses equivalents too.

[ivanvernon]

Here are three handheld JPEG unprocessed shots from a Chinon 50 mm f 1.9 picked up for $30 from eBay.