Canon 50mm f/1.4 vs. f/1.8
I did go ahead and purchase the Canon EF 50mm f/1.4 USM Medium Telephoto Lens (pictured at right).
For an extra $225, you get a faster lens (f/1.4 vs. f/1.8) and a much much higher quality build. It features an ultrasonic focus motor that is quiet, smooth, and very fast (unlike the loud and clunky focus motor in the Canon EF 50mm f/1.8). The f/1.8 lens has a metal mount and is about 3x as heavy as the f/1.4 50mm lens.
Optically, it is a superior lens, but not entirely!
Now that I have both lenses, I’m actually torn about parting with the f/1.8 super-cheapo lens. A little bit. Not much, though.
Read on for details…
My previous criticism of the Canon 50mm f/1.8 lens is that the BOKEH — the blurry background bits of portraits and the like — is unpleasant. Now, I also fully admitted that I was, at the time, using the lens in a context that would have been better served by the Canon 100mm Macro lens.
So, I set up a shot that was more portrait like. A small vase with a fall crocus. Note that it was windy, so taking advantage of the quick shutter in the bright sun was a definite boon.
The image on the left is the Canon 50mm f/1.8 lens (1/4000th of a second) and the one on the right is from the Canon 50mm f/1.4 lens (1/3200th of a second). Both shots were taken at f/2.2.
The foreground is relatively similar between the two images. The f/1.8 actually looks a little sharper, but that is mostly because I had to move the bottle slightly and a lighter side is facing the camera.
The background, however, is markedly different. Huge difference! The Canon 50mm f/1.8 lens’s background looks like it has a pox! There are weird lines and scallops of color throughout whereas the Canon 50mm f/1.4 lens produced a nice consistent bit of background blur.
This is also where I’m torn. The f/1.8 lens seems to gather more light at smaller apertures; 1/3200th vs. 1/4000th of a second for this shot. It performs similar in lower light situations. Thus, unless I’m shooting at the wide open f/1.4, the f/1.8 seems to be better at capturing low light shots. Even if the background isn’t as pretty and the foreground isn’t as sharp, successfully taking a picture is always superior to missing the shot. Came as a complete surprise!
In this case, the top photo is from the Canon 50mm f/1.4 at (f/2, 1/1600th of a second) and the bottom is from the (f/2, 1/1600th of a second).
The f/1.4 is simply brighter and sharper. Flat out better quality image to my untrained eyese.
Unlike just about every other photo, I have not done anything to these images other than rotate one just slightly and crop the vase / flower a little bit.
I also disocovered that the Canon digital rebel xt simply cannot deal with purple petunias. Actually, in general, Canon cameras completely fail to correctly expose certain shades of purple flowers in bright sunlight.
I have no idea how other bodies or brands might perform. It is a serious enough oddity that I should probably document it and actually try to get some decent photos of these damned flowers!
October 18th, 2007 at 6:56 pm
Thanks for the comparison. I have seen many people blather on about bokeh but never saw anybody actually doing a side-by-side comparison of reasonably similar lenses. Yes the difference is visible. (But I think it’s much less dramatic than many would claim it is.
Perhaps a part of the different exposure times you got is due to there being more dark background on the photo taken with the 1.4. This may have led to the image being darker on average and it led to the whites on the vase seeming slightly overexposed and flatter than in the photo taken with the 1.8.
I find the landscape photo hard to judge. I’d like to think that a smaller aperture might have evened things out between the lenses and given you more things that aren’t out of focus. (It may also be worth noting that you probably want to look at the full size images rather than the potentially poorly shrunk + JPEG compressed little ones flickr gives you.)
October 19th, 2007 at 7:49 am
Purple flowers in bright sun are a general problem. My Nikon D50 can’t handle them either.
December 22nd, 2007 at 5:03 pm
In your second example the photos are focused differently. The 50 f1.4 is correctly focused on the background. The 50 f1.8 is focus is nearer to the camera. The 50 f1.8 still has a lot of corner softness at f2. But in your example the lower left corner is sharper with the 50 f1.8 lens due to the differences in focusing.
February 22nd, 2008 at 2:28 pm
Could it also be the “brighter” picture you’re seeing is a result of better glass and more contrast on the 1.4 over the 1.8? Cheap lenses often blow out and show a bit more color. They refract a little more light internally as well rather than trapping stray light. All of that will lead to faster shutter speeds and/or brighter images… but not necessarily better quality.
In my experience, too, the difference between 1/3200 and 1/4000 is minimal. Take five shots with the same lens within five seconds and you’ll often see the camera bounce back and forth between 1/3200 and 1/4000 (or even more). It doesn’t take much - just a teeny bit more cloud to obscure the sun or something - to flip the camera between such relatively similar shutter speeds.
March 1st, 2008 at 2:56 pm
Nice post.
I’m a Nikon owner and have their 50mm f1.8 AF. I understand from a friend that the Nikon 50mm f1.4 is by no means as obvious choice over the cheaper f1.8 - the build quality doesn’t differ so much and the extra speed doesn’t give any better quality photo.
June 28th, 2008 at 5:12 pm
Learn to grow flowers and vegetables that make some of the most beautiful pictures in the world. I personally do not take the pictures as stills, but video them as they are growing and then take stills from those videos. This may not be the best way to do such things but it is one of the best that I find simply because I watcht the videos anyways, and as I am watching if I see something that I eaither want to use or think will make and extraordinary picture then just simply click the take snapshot buttom on my video viewer. See some of the pictures that I use.
http://gardening-for-profit.blogspot.com/
July 14th, 2008 at 4:39 am
@ Mike Gilchrist: What do you mean by videoing the flowers as they grow? Does this mean you actually record the whole process like they do with the moon cycle at night? Sorry for my ignorance but I recently got into photgraphy (hobby mind you) and I would like to know how you do this.
Thanks kindly
Andy