f/1.8 vs. f/1.4

How much of a difference will 1.4 get me versus 1.8? Say I'm using 1.8 with 1/20th for shutter at 100 iso what kind of shutter speed would i get with 1.4? I'm trying to decided if the 50 1.4 is worth it, in terms of aperature, compared to the 1.8.

If thats all that matters then get the 1.8. There is more to it than that as far as the differences to those lenses. The 50 1.4 is every bit worth it and to me is just as good a value for money as the 1.8 version. But thats because I value the other differences, such as better more solid build, faster more accurate focus and a much nicer bokeh, atleast in my opinion.

I've seen decent bokah with both so not sure if that critique re. the 1.8 is entirely valid. Many use it as a reason to get the 1.4 but I dunno. I've never used the 1.4 so this is just an observation of shots I've and shots I've taken in the past. I guess it's a personal cost/benefit thing.

I've owned both. The 1.8 has circular looking rough bokeh. To some that may be fine and may be even preferred. I don't like it. The 1.4 has a much smoother looking bokeh similar to that of the 70-200L F2.8 IS that I have also owned. I find most people that buy the 1.8 because its cheaper than most filters I've bought and gives an excellent sharp photograph. Nothing wrong with that. I also beleive you get much more for the extra money with the 1.4.

Here is an example just to illustrate.

The 1.8 version

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I've got the 50mm f/1.8, but will be upgrading to the f/1.4 version.

The simple reason is that the 1.4 is USM, and the 1.8 is not. I'm completely happy with the quality of the shots I have from the 1.8, but it simply focuses too slow for me...

Steve

This has been debated in the forum a lot of times. It's really up to the individual because the 1.4 is twice or more the price of the 1.8. How often are you going to use it? Do you have low light issues? Does construction matter to you? I just purchased a 1.4 and used it for 3 shoots. It is a sharp lens, really fast, and just so small, you can hardly believe it. I never considered the 1.8 because most of the people who have opinions on the two say the 1.4 is worth the extra money. I just went for it. My husband blames the forum people. It's okay.

SuzyView
10D, 20D in the mail, EOS 3, and lots of stuff

See (on old post) https://photography-on-the.net ….php?p=406267&p​ostcount=2

Thanks for that link pekka. Seem that the f/1.8 will be just fine. I'm not particularly looking for the USM and build of the f/1.4. I'm looking for a lens that will be effective in low light of restaraunts and such, where a flash wouldn't be appropriate. Based on that table which is ISO 100, with the jump to 200 or even 400, the f/1.8 seems to satisfy my needs and is a bargain in terms of price.

Poe. No one answered your question. The difference is about 2/3 of a stop so you would only obtain 1/30 (1/20 - 1/25, 1/30) with the f/1.4 vs. f/1.8.

The progression for 1/3 stop shutter speeds is 1/20 - 1/25, 1/30, 1/40. You know that aperture f/stops and shutter speeds are reciprocal right? Those of us old timers who came from film memorized the reciprocal tables, and we only had full or half stops, not thirds!

Frankly, not enough of a difference since recent digital cameras have such excellent high ISO performance, you would raise the ISO to 400, gaining 2 whole stops to shoot @ f/1.8 & 1/80 (1/20 - 1/25, 1/30, 1/40 1/50, 1/60, 1/80) to be remotely hopeful of a sharp photo with a 50mm lens on a 1.6 field of view crop camera.

IMHO, if all you need is low light, not creative defocused background, use a nifty fifty f/1.8 and raise the ISO. If good quality creative defocus is your goal, the Canon 85 f/1.8 provides smoother background blur than either of the 50mm lenses, and has a real USM focus motor instead of the crippled junky thing in the 50 f/1.4. Despite the accolades it gets on the forums, I think the 50mm f/1.4 is an overpriced for auto focus users. Manually focused in a studio, sure.

Jack

Here's a link to a lab test for the 1.8. There is also a test of the 1.4 on the same website. There isn't much in it regarding image quality, but the 1.4 is a tad better. So for the extra money you get better build quality, a nicer MF ring, a slightly wider max aperture and perhaps a small improvement in image quality. Personally, I can't justify the difference in price. That's a call only you can make.

http://www.photozone.d​e …ses/canon_50_18​/index.htm

Based on that EV reading, shooting ambient light @ f/1.8, you will need at least ISO 800 for a shutter speed of 1/160 minimum to avoid blurry ugly facial gestures and hand movements of people in a restuarant.

One benefit of flash in low light is to freeze motion. I frequently find I need to use ISO 1250 (on the I-D Mark II) in low light, and ISO 1600 on a Canon 20D when doing ambient light. Or just under expose by one stop, shoot RAW, push process the exposures and remove the noise.

Jack

I agree. The bokeh from the 1.4 seems much more pleasing to me.

uktrailmonster wrote:
Here's a link to a lab test for the 1.8. There is also a test of the 1.4 on the same website. There isn't much in it regarding image quality, but the 1.4 is a tad better. So for the extra money you get better build quality, a nicer MF ring, a slightly wider max aperture and perhaps a small improvement in image quality. Personally, I can't justify the difference in price. That's a call only you can make.

http://www.photozone.d​e …ses/canon_50_18​/index.htm

I think it all comes down to maybe how much you use the lens. If you use it alot, some of the minor annoyances of the cheaper version can become unbearable. I agree with the poster that said the 85 1.8 is better. I love that lens. Some don't like the longer focal length on a 1.6 crop though and feel that the 50 provides more use indoors where space is limited.

That's because the 50 1.4 has more blades than the 50 1.8, giving it that chance to give a smoother bokeh. It's pretty just like the 70-200 IS's bokeh.

One advantage the 50 1.4 has, its more accurate in low light/more consistent and less likely to hunt. Now how often does that happen? I don't know, but if that's not a concern to you, go with the 1.8 if all the other things don't concern you either.