My 50/1.8 vs. 50/1.4 AF lens Test

[dan_brown14]

To settle this debate for myself, I conducted this test today. I used a D100 on a Bogen

3021 with self-timer and mirror anti shock function enabled. Both lenses set to f1.8

under overcast skies. The 1.8 required 1/1500 sec. exposure, the 1.4 required 1/2000. I

think the light fall-off of the 1.8 forced this difference.

 

The images below are the full frame, resampled to 500 pixels wide, and a 500 pixel crop

from the upper left hand corner of both NEF files. They were all saved as JPEGs for posting

here.

 

The 1.8 exhibited noticeable light fall-off in the corners, the 1.4 did not. The 1.4 is

sharper in the corners, and appears a touch warmer to my eyes. I believe the 1.4 is a

better lens than the 1.8.<div></div>

[dan_brown14]

50/1.4<div></div>

[dan_brown14]

50/1.8 cropped 500x333 pixels<div></div>

[dan_brown14]

and, the 50/1.4 cropped to 500x333 pixles<div></div>

[c_o1]

Dan,

I use the 1.4, which I love dearly. But I think the 1.8 looks better in this test. Can you

post some more? Maybe focusing closely on something at f4?

Thanks,

CO

[vivek iyer]

Interesting response, CO. I can't notice any difference.

 

Dan, Thanks. I do seem to notice (could be wrong, my monitor isn't all that great)a slight amount of color fringing on the 50mm 1.8 crop compared to the 1.4 crop. Is that what you see? Also, did you use any filters/hoods on the lenses?

[g thomas]

I really don't see much difference either. But I would hope the 1.4 would be better considering the price difference. The 1.8 is good enough that I consider it one of the best buys I've ever made in a new lens. Also, is there any difference at f8?

[larry n.]

Dan,

 

Conventional wisdom is that the F1.4 lens would be sligthly better than the F1.8 lens at F1.8 and maybe even at F2, so you are not proving anything new here. At f2.8 to f8, the slower lens should be better.

 

However, in the test you posted, the f1.8 looks better. Go figure!

[frank granovski]

The 50mm F1.8 is the better lens. I owned both, though they were the manual versions. Another very sharp lens is the 28mm F2.

[michaelkh]

When I bought mine, I asked myself:

 

a) is it twice-the-price better?

b) is that two thirds of a stop worth the doubling in price?

 

For me, the answer was no in both cases, and the difference bought either a whole cosina

100mm macro, or a good slice of a tripod, both of which certainly have had more impact

on the sharpness of my photos than the f/1.8 -> f/1.4 transition would.

 

I guess I'm not a lens nerd, but even then, I can't see what I'm missing...

[dan_brown14]

I was interested in wide-open performance, as this is where I find such lenses most useful.

Stopped down, I'd likely go with a zoom for convenience anyway.

 

Both lenses were clean, no damage or anything, and no filters, both had hoods in place

(Nikon HN-7, which is a deep 52mm screw-in hood. I'm not a lens tester, and it takes

quite a bit of time to runs these, process them, etc. So don't look for much more from

me. The results confirm what I wanted to know (frankly, I was starting to wonder if the 1.4

was a dog, or something, and if I'd bought the wrong lens).

 

To me, the 1.4 crop is considerably sharper, look at the three arched windows on the

upper floor to the right. With the 1.8, the window molding is barely discernible, with the

1.4, its rather clear. Ditto for the two smaller half-round windows. When I A:B these full

frame on a Mac in Nikon View, the light fall-off of the 1.8 is readily apparent vis-a-vis the

1.4, but as a practical matter, the 1.8 fall-off is probably no big deal.

 

I think the f1.8 speed of the 1.8 is an optimistic rating, the shutter speed difference and

darkening of the corners leads me to believe it's really a 2.0 w/marketing. Perhaps it's 1.8

inn the center, I dunno. I belief the 1.4 is a good stop faster, which is valuable in and of

itself for me.

 

I've also posted about my earlier tests re: coma distortion in the 1.8. Again, this may not

be a big deal unless you do night shots with point light sources. At any rate, it does point

to the fact the the 1.8 is less corrected for higher order aberrations, which is expected

given that it has one less element and the price point.

 

I didn't notice the color fringing, but I'll take a look at the NEF in Capture at 200% or so,

and see it I can notice it there.

 

The question of value for speed is a personal one, the folks over in the Leica Forum

discusses this a lot, and Leica's lens pricing (e.g. Elmar, Summicron, Summilux, Noctilux)

is the poster child for speed versus value. My wife has had the 1.8 for a few years, and I

just bought the 1.4 this week for $279. All things considered, the 1.4 is a real bargain.

[albert_smith]

Two things to consider...

 

The weakest part of a lens' rendering at full aperture is at the edges. These two lenses can be used on full frame film cameras, where that edge performance would be part of the overall performance. With digital, you don't see that part of the image since it falls outside of the capture surface. This can give the impression of perfomance that might not be equal to what film shooter might experience. On film, my f/1.8 lens has better edge performance over my f/1.4 lens, which would mean that if I need sharpness across the frame, the f/1.8 lens would be the one I would choose.

 

A lot of lenses are optimized for best performance well inside of infinity. The usually standard is 50 focal lengths, which is about 100 inches for a 50mm lens. Again, the test presented above might not show what is important for a normal use of a 50mm lens in the 6 to 10 foot range.

 

So... a single test using a single subject at a single distance would not be enough to say one lens is better over another for every situation. Unless of course, every subject you shoot is the same as the test subject.

[mark_sirota1]

Dan, the difference in the corners could be explained by your choice of the HN-7 hood, which is designed for lenses longer than 50mm. Depending on the optical formulae of these lenses, it is possible that the 50/1.8 suffers more vignetting than the 50/1.4 due to the intrusion of the hood. It would be interesting to run this test again with no hood, or with the hood designed for these lenses.

[frank uhlig]

I wonder, I wonder.

 

We cannot change the weather, but I would not personally shoot this scene on a sullen day. How about a test with sunlight, contrast, colors other than only pale grays and greens.

 

Or going to the other extreme, how about a lens shootout in dense fog, gray pea soup with a single recognizable bush (black) in the foreground. How would the lenses compare then?

 

I would not care to know, would anybody else? Sorry, nothing proved here today. But on a sunny day, the table turns into opportunities galore!

 

Sorry. it was not a good day/time for a meaningful test today.

[johnw63]

The detail around most of the windows are a bit better with the 1.4. Since the camera used was a digital,and has a smaller sensor than 35mm film does that mean we really don't see the "true" edges that the lens can capture ? If so, does that help a lesser lens by in camera "cropping" the edges, where they might often show fall off ?

[angel_o.]

I'm wondering on the exposure difference of 1/2 stop. I doubt that the 50/1.8 or the 50/1.4 are 1/2 stop off. In addition, it's logic that the 50/1.4 is at f/1.8 sharper than the 50/1.8 (though the contrast of the 1.8 looks in this shot more appealing to me) but what about f/4? For me the question is not which lens is sharper wide open to decide wether the 50/1.4 or the 50/1.8 should be first choice. The question for me is, do I need the faster glass at twice the price? In any case, you can't go wrong with either one.

[lex_jenkins]

Dan, your sample photos using the f/1.4 are slightly contrastier and clearly sharper. This is visible in the crop when looking at any hard edges such as the window frames and roofline.

 

No comment on the warmth, color quality or anything else. I can't see it in these particular photos.

[bruce_rubenstein___nyc]

Discussions about the 50/1.4 vs. the 50/1.8 are similar to how many fairies can fit on the head of a pin. Yes the 1.4 has less light fall off at 1.8 than the 1.8 one does, and is also sharper. But wide open, the 1.4 has worse light fall off and less sharp than the 1.8 (at 1.8).

[vivek iyer]

Significant light fall off on a puny DX sensor?

 

Now, what if the D100 sensor(and the image output one gets out of it) has its limitations to discern any difference in the sharpness offered by either 50mm lenses?