Why pay 3X more for f/1.4 versus f/1.8?

[kirbinster]

We all know that fast glass costs more money, for many reasons. But what is the real world difference between shooting wih say a 50mm f/1.4 versus f/1.8, or for that matter an 85mm f/1.4 versus f/1.8? Assuming you are not at the very edge of the lens capabilities, is there really any difference say if you were shooting at f/4 with either lens? In other words, what is the justification for spending 3X as much for a lens that is not really that much faster than the other?

[Japaslavian]

There's this for starters:
Canon EF 50mm – F1.4 vs F1.8 MK II - photo.net

That, and the build quality of the 1.8 is pretty shoddy. The plastic body is flimsy, the AF to MF switch feels like it's going to break off when you move it, and my auto-focus broke for seemingly no reason. If you can afford it, I would totally go for the 1.4. Compared to many other lenses, the 1.4 is still quite affordable, especially for what you get out of it. Also, the focusing ring on the 1.4 is not the same as the filter ring, where as the 1.8 is.

[Raoul Isidro]

A few reasons I can think of:
1. Glass / there's almost double the volume between the two lenses when you view the cross section diagram. The coatings and polishing of the 1.4 is also more rigid and enhanced.
2. Motors / the 1.4 is USM and the 1.8 is not. The gear mechanism of the 1.4 is more complicated but better in terms of user ease.
3. Materials / the glass, chassis, plastics etc. all account to a price difference
4. Precision and tolerance / more R&D done on the 1.4
5. Prestige / there is a reason why Nikon and Canon use the 1.4 as the "cover" lens for their new model cameras, even in the past film eras. It is the pride of their lens research.
Cheers!

[Nicole]

Subjectively I think that between my shots with my old 1.8 and my new 1.4, the 1.4 shots seem to have better contrast all around. Not that the 1.8 wasn't a beauty of a lens, but when it came down to deciding to replace it, I went with the 1.4 and (subjectively) saw a noticeable difference to contrast without post-processing. I opted for the D version though, rather than the G version because the price was essentially 2.5x more for the D version, compared to 5x more for the G version.

[OsmosisStudios]

It's not just 2/3 of a stop aperture. In many cases the lenses are worlds apart at the same apertures up to f/2.8, which is where they're most likely to be used. I know in the case of the Nikon 50s, too, the 1.4G is an AF-S lens, which comes with it's own set of pluses.

There's a reason the NIkon 85 1.4 is called the Cream Machine, too.

[LoveDSLR]

Ignoring the aperture, build, and other obvious factors, I would say we are paying for the lens signature.

For example, I'll ignore the 85 f/1.8 for portraits and only consider the 85 f/1.4 'a.k.a. the Cream Machine'. If I'm looking for the sharpest lens then I'll buy a macro lens.

Regarding the 50 f/1.8, I consider mine liked a bicycle training wheel and haven't used it for decades.

[kirbinster]

I fully understand build quality issues, but that is not what I am asking about. I understand that a D300 costs more than a D90 - yet both will take the exact same image. So, you pay more for the D300 to get things other than pure image quality. What I would like to see, if anyone can produce it, is the exact same picture taken with an 85mm f/1.4 lens and one with an 85mm f/1.8 lens (or with 50mm lenses). What I am after is to be able to see a realworld example of how the image from the one lens differs from the image taken with the other lens.

I have the Sigma 50mm f1.4, and gave away my Canon 50mm f1.8...otherwise, I'd go shoot an example for you.

I like to shoot very low f-stops for portraits and photojournalistic style photos...the lower, the better. At f2.0 (where I shoot), the Sigma is much sharper than the Canon. It focuses much faster as well. Most of the time, that's the lens that is on my camera.

Here's my advice...if you regularly shoot weddings or other low light situations, spring for the 50mm f1.4. If you don't, the 50mm f1.8 will probably be fine.

[kirbinster]

Originally Posted by Photoboothguy

I have the Sigma 50mm f1.4, and gave away my Canon 50mm f1.8...otherwise, I'd go shoot an example for you.

I like to shoot very low f-stops for portraits and photojournalistic style photos...the lower, the better. At f2.0 (where I shoot), the Sigma is much sharper than the Canon. It focuses much faster as well. Most of the time, that's the lens that is on my camera.

Here's my advice...if you regularly shoot weddings or other low light situations, spring for the 50mm f1.4. If you don't, the 50mm f1.8 will probably be fine.

Thanks but I don't think it fair to compare two different brands. I had a Sigma 24-70 f/2.8 which I replaced with a Nikon 24-70 f/2.8 and the difference was HUGE. You have to compare within the same mfg line to be comparing apples to apples.

[Digidave]

Here you go.

http://www.smartpict.com/lenstest/Nikon_50_18_VS_50_14/US_test_Nikon_50mm_14_VS_18.php

To be honest, I'm really surprised how much difference there actually is.