Canon 50mm f/1.4 soft at f/1.4, f/2, f/2.8, f/4 sharp at f/5.6, f/8

[Abitconfused]

My lens is soft until f/5.6 & f/8 then sharp as a tack. Seems at little silly to buy a fast soft lens. Would a slower (cheaper) lens be best if resolution is a goal?

[pentaxpete]

I agree -- when I got my LEICA M2 it came with the 35mm f1.4 Canadian-made Summilux and it is really 'soft' at f1.4 -- not sharp enough for my local Press Photography work -- then I got a 1985 M6 the the German version so I have TWO to compare -- both 'soft' at f1.4 and even a third sample I borrowed from a friend -- OK at f2 and lower -- then I have a Canon FTBn with the Canon 50mm f1.4 lens and it IS useable at f1.4 allowing for shallow depth of field of course -- I also have the 50mm f1.4 SMC Pentax-M lens I use with a Pentax LX and 'sometimes' it is sharp at f1.4 -- maybe the focus is a bit out ?

Here is the LEITZ 35mm f1.4 Summilux at f1.4 in the Gothic Cathedral, Barcelona

Barcelona 2 by pentaxpete, on Flickr
Here is my Canon FTBn with the Canon 50mm f1.4 lens

Canon FTbn by pentaxpete, on Flickr
At the moment I cannot find any F1.4 shots taken with the Canon lens to show you

[Manfred M]

Ed - People buy super fast lenses for their maximum aperture settings to get either good low light performance or shallow depth of field and are willing to trade off a bit of sharpness to get those features. If you want to save yourself a bit of money, you will find that f/1.8 50mm lenses are technically a bit sharper wide open than the f/1.4 50mm. As a general rule, stopping down 2 or 3 stops will indeed get you into the optimal sharpness range of a lens; once you get past f/8 or so, diffraction will start reducing your sharpness.

This may be true, if you get into pixel peeping. Unless you are shooting using a very stable tripod and ensure that your focus is spot on, this all becomes somewhat irrelevant. In real life photography you are unlikely to notice the difference.

The fastest lenses that I currently own are a f/1.8 35mm and a f/1.8 50mm lens because I couldn't justify spending the money on the faster models. I generally only use these two lenses as walk-about lenses and their low light performance and depth of field are perfectly adequate for the shooting I do.

[William W]

My lens [Canon EF50 F/1.4] is soft until f/5.6 & f/8 then sharp as a tack.

Possible, but in my experience not plausible.
Are you sure your testing method is beyond reproach?
If you are 100% certain that your EF50/1.4 is soft until F/5.6~F/8 – then I’d suggest you return it as defective.

In my experience (I have used three of these lenses) and those three EF50F/1.4 lenses have been acceptably sharp at F/1.4 in the centre and a little bit softer softer at the edges.

At F/2.2 the centre is very sharp and the edges lack behind only by a very minor tad and is not seen in mostly all images, except test charts.

The Plane of Sharp Focus of this lens is reasonably flat.


F/1.4:



*
F/2.2:



***

Would a slower (cheaper) lens be best if resolution is a goal?

IF you want the sharpest of the four Canon 50mm lens available for purchase new at the moment: then buy the EF50 F/2.5.

***

. . . you will find that f/1.8 50mm lenses are technically a bit sharper wide open than the f/1.4 50mm.

Hi Manfred,

I am not convinced that the EF50F/1.8MkII is sharper at F/1.8, than the EF50F/1.4 is at F/1.4.

I have only used the EF50F/1.8MkII for a short period of time and that short time did not allow me to do adequate bench testing of the lens wide open, but I was testing three of the 50mm Canon lenses to decide upon a purchase, so I did give the EF50F/1.8MkII a good run through . . . this comparison chart indicates to me, that my feelings are correct.

WW

[Bobobird]

At 1.4 the usual culprit is the photographer and his hand-holding technique. DOF is sooooooooooooo thin that even a tiny little bit of movement while taking the shot will make the shot look soft. That is why lots of people recommend using it at f2 or higher.

But if yours is only sharp from f5.6 onwards it is possible that the lens is defective. Get a replacement either way as a negative feeling about this particular copy will always niggle at you.

These shots were all taken at f1.4. ISO 1600 or thereabouts, AV mode so shutter speed would be variable, with a 550D.

1.


2.


3.


4.

[Abitconfused]

I'm going with operator error. Must test on tripod!

[Manfred M]

Hi Manfred,

I am not convinced that the EF50F/1.8MkII is sharper at F/1.8, than the EF50F/1.4 is at F/1.4.

I have only used the EF50F/1.8MkII for a short period of time and that short time did not allow me to do adequate bench testing of the lens wide open, but I was testing three of the 50mm Canon lenses to decide upon a purchase, so I did give the EF50F/1.8MkII a good run through . . . this comparison chart indicates to me, that my feelings are correct.

WW

Bill - you could be right. My comments are generic and are based on shooting with Nikon and Leica 50mm lenses. In both cases the corner sharpness of the f/1.4 was not quite as good as the Nikkor f/1.8 or the Summicron f/2. This has tended be a reasonable rule of thumb across the manufacturers offerings for many years.

I shot my nephew's Canon 50D with the f/1.8 50mm lens back in the summer and what struck me was that it had to be the cheapest feeling prime I've ever used. Optically, it was quite sharp and it was a nice portrait lens, although I've seen nicer bokeh.

[William W]

My comments are generic . . .

Yes I assumed (and remembered) that you use Nikon and that the statement was a generalization.
My reason for commenting was because the OP specifically is discussion Canon 50mm lenses - and I happen to have used many of those particular 50mm lenses.

WW

[Shadowman]

At 1.4 the usual culprit is the photographer and his hand-holding technique. DOF is sooooooooooooo thin that even a tiny little bit of movement while taking the shot will make the shot look soft. That is why lots of people recommend using it at f2 or higher.

But if yours is only sharp from f5.6 onwards it is possible that the lens is defective. Get a replacement either way as a negative feeling about this particular copy will always niggle at you.

These shots were all taken at f1.4. ISO 1600 or thereabouts, AV mode so shutter speed would be variable, with a 550D.

1.


2.


3.


4.

Don't you find it difficult to measure sharpness when your subject is moving?

[gcowan]

At 1.4 the usual culprit is the photographer and his hand-holding technique. DOF is sooooooooooooo thin that even a tiny little bit of movement while taking the shot will make the shot look soft. That is why lots of people recommend using it at f2 or higher.

But if yours is only sharp from f5.6 onwards it is possible that the lens is defective. Get a replacement either way as a negative feeling about this particular copy will always niggle at you.

These shots were all taken at f1.4. ISO 1600 or thereabouts, AV mode so shutter speed would be variable, with a 550D.

1.


2.


3.


4.

When I needed a 50, I bought a Canon EF50 f1.4 because it performed so well on the tests that I read. I have not been disappointed with it, but I don't shoot it wide open very often because of my subject choice. When I do I am happy with it. It is no Leica Summilux but then it is 1/4 to 1/8th the price. Have yours checked out.

BoBo, those are very beautiful street photos. If you are shooting these at f1.4, that is some technique you have. I would love to see see more of them.

Graham

[gcowan]

At 1.4 the usual culprit is the photographer and his hand-holding technique. DOF is sooooooooooooo thin that even a tiny little bit of movement while taking the shot will make the shot look soft. That is why lots of people recommend using it at f2 or higher.

But if yours is only sharp from f5.6 onwards it is possible that the lens is defective. Get a replacement either way as a negative feeling about this particular copy will always niggle at you.

These shots were all taken at f1.4. ISO 1600 or thereabouts, AV mode so shutter speed would be variable, with a 550D.

1.


2.


3.


4.

When I needed a 50, I bought a Canon EF50 f1.4 because it performed so well on the tests that I read. I have not been disappointed with it, but I don't shoot it wide open very often because of my subject choice. When I do I am happy with it. It is no Leica Summilux but then it is 1/4 to 1/8th the price. Have yours checked out.

BoBo, those are very beautiful street photos. If you are shooting these at f1.4, that is some technique you have. I would love to see see more of them.

Graham

[Bobobird]

Thanks guys.

Sharpness + moving subject - I think that with street photography the most important thing to do is not dwell on the shot. Beep/shoot is what I do.

As for more - need to dig up and post in another thread. No wish to hijack this one.

Though the 1.4 is always in the bag, the birds/bugs demand the other lens so it has been very neglected.

[William W]

Depth of Field depends upon a range of factors and one is Subject Distance.

Using F/1.4 does NOT necessarily mean that the DoF is always super shallow.

For example and on a technical note about those four street samples (if the first three are all a full frame crop out of the camera) – there is actually a relatively large Depth of Field in all except the second – which has the least of the lot:


In the first shot there would be about 4’6” Depth of Field

The second has about 11inches DoF

The third has about 2’4” DoF

The last image is obviously cropped, but the must be at least 2’4” DoF, perhaps more, depending upon how the image was cropped.

(based upon CoC = 0.016mm)

***

Here is an example of really shallow DoF using the EF50F/1.4 on an APS-C camera (EOS 20D) it is also an example of using very high ISO on that particular camera. This shot was made at F/1.6 and the DoF is about 2~3inches:



F/1.6 @ 1/50s @ ISO3200; HH; Manual.

***

IF we move the lens to a 135 format camera (aka ‘Full Frame’) then the DoF is relatively thinner.

Here is an example using a 5D which just about mimics the second shot in the street series above:



This shot also has about 11inches DoF . . .
but . . . F/2.2 was used to make this shot as contrasted to using F/1.4 with the 50mm lens on the EOS 550D for the second street shot, of the Guitarist.

WW

[Bobobird]

Thanks Bill.

Distance to subject matters of course. I use mine primarily for night time street shots to get as much light as possible without having to up the iso too much.

A couple more examples.

f1.4






f1.8 cropped


f5.6