Tuesday, January 26, 2010

The Normal lens (updated)

When I bought my first camera in the seventies, zooms were expensive and not very good, and there was no such thing as a kit zoom lens, one sold with the camera in a bundle. (I think Fuji came out with the first one in the late seventies.) But since then, zooms have become better and cheaper, and everybody wants them. But there are still reasons to use prime lenses, such as cost, weight, size, and fidelity. Even the cheap 50mm lens can be surprisingly good and versatile.


It should be noted that on a DSLR camera (unless it's an expensive full-frame one), a 50mm lens is no longer a "normal" lens, it's more to be regarded as a shortish portrait-length lens.

Of course not all 50mm lenses are equal. For example, one of the first lenses I got when I first aquired a good digital camera (Nikon D100, back in 2002) was Nikon's 50mm 1.4. But unfortunately my dreams of creamy soft backgrounds were dashed by that lens's dreadful "bokeh", meaning the blur is uneven and edgy, not smooth. In contrast, I recently got Pentax's 50mm 1.4 AF lens, and it has beautiful bokeh (and is sharp too).

Nikon 50mm at 1.4:

Pentax 50mm at 1.4:

... One should note that bokeh is very subjective, and also changes a lot with the light, with distance, with the kind of detail in the background, etc...

Update: Steve said:
As for bokeh, just watch for the number of blades in the lens. More is better as a general rule.

That is true. Because except for full aperture, with spot-shaped out-of-focus highlights, one will see the shape of the diaphragm in them, and most find a circular shape best.
But: another important factor is whether a point-shaped source of light gives a disc of light with more light in the center as is natural, or more near the edges. The latter often happens with lenses with aspherical elements, and tens to give edges within the blur, and to make "double lines" of edges in the blur.

18 comments:

Anonymous said...

A fast (sub 2.8) 50 or equivalent is a must to have in one's kit. First lens, unless you got it with the initial buy. The faster lens and more aperture blades you can afford, the better. Even the less expensive ones are worth owning.

Anna said...

Interesting !

Well, the backgrounds are so different I cannot really compare. But I really love Pentax blurred backgrounds, so if you tell Nikon doesn't do that so well, i certainly agree. :-)

Timo Lehtinen said...

What? Today's cameras are technically better than those from 2002? How can that be? ;-)

Zooms in the 1970s were more expensive and not very good? But since then, zooms have become better and cheaper?

Come on, you must be pulling our leg ... ;-)

Either that, or you really dropped a bomb here ...

TC [Girl] said...

Thanks for the info, Eo & Steve! Good to know! Now, I just need to figure out what kind of tripod to get! :-) Any recommendations?

ttl: "...you really dropped a bomb..."...as in this? ("I-I-I I-I-I...") ;-)

Eolake Stobblehouse said...

Anna,
Unfortunately one can't just conclude that Pentax is better than Nikon, not even in this small area. It might happen that Nikon has an altered version out which is much better, one can never know. And their 1.8 lens may have great bokeh.

TTL, I'm sorry to keep irritating you with this kind of writing. But I felt it was relevant background information here, and many from the younger generations are not aware of a time when zooms were not the easy choice, and so they may not understand why a 50mm lens exists at all, much less why one would want to own one.

And by the way, apart from resolution and high-ISO performance, the D100 from 2002 holds its own pretty well. I still have prints framed on my wall which I too with it.

Eolake Stobblehouse said...

I think a carbon tripod with a largish ball head is a good option.

Anna said...

>Unfortunately one can't just conclude that Pentax is better than Nikon, not even in this small area.

Of course not ! :-)

I was just pointing out that I like Pentax... and that as I lack information about Nikon, I use my Pentax-nationalism to judge it ! Which is of course not a very serious attitude...

Anna said...

> The latter often happens with lenses with aspherical elements, and tens to give edges within the blur, and to make "double lines" of edges in the blur.

Interesting, now I see the difference.

Just a remark: if I take my glasses off and look far, i do see double lines with my eyes... So maybe the double lines are kind of more natural. Though I really live Pentax blur.

Eolake Stobblehouse said...

Or maybe your eye lenses are aspherical.

Eolake Stobblehouse said...

I would love to be brand-biased, but it makes me so skitzo, since I use Pentax, Panasonic, Canon, and Nikon.

emptyspaces said...

My Canon 28/1.8 is almost dead-normal on my 40D. It's an underrated lens, pretty good bokeh. 7-bladed aperture.

Miserere said...

I don't know, I wasn't there, but I have used many great zooms from the early 80's, and they were better than most modern zooms I've used. Manual focus, of course, but optically great.

The Tokina SZ-X 28-70mm f/2.8-4.3 comes to mind. Small, sturdy, and sharp at all focal lengths from wide open. I can't even say the same thing of my Tamron 28-75mm f/2.8 (allegedly a better optic), which is my favourite walk-around lens.

Zooms have got smaller and lighter, but unless you're shelling out big bucks, they're not better than they used to be. That's my opinion, anyway.

Eolake Stobblehouse said...

I must admit I have not tested that claim myself, back in the day I only used prime lenses, for economic reasons.

But they must also have been pretty expensive back then?

The kit zooms I have, in newest versions, I think are good quality optically, and at at totally negligible price as well as weight.

TC [Girl] said...

Eolake said...
"I think a carbon tripod with a largish ball head is a good option."

Thanks for the suggestion, Eo. I appreciate that.

Anna said...

> I would love to be brand-biased, but it makes me so skitzo, since I use Pentax, Panasonic, Canon, and Nikon.

Haha ! :-)

You don't need to.

AS I use only Pentax, I would be skizo is I was dreaming of a lot of other brands. :-)

BTW, I think this is the only area in life where I am branded. :-)

Barrie said...

I have used Canon 1.2 and Konica 1.4, both very good, I much prefer either to Pentax or Nikon lenses but none of them are not to Zeis.

Barrie said...

That`s not right, the end of my last post should read none of the are equal to Zeis.

Eolake Stobblehouse said...

Zeiss has a stellar reputation. I have heard though that they are not right for everything, because they have a certain hard, contrasty quality.