I won't claim to be an expert on depth of field, but seems to me that if both the f/1.8 lens and f/1.4 lens are set at f/4.0 each will have the same depth of field, no matter which manufacturer made the lens.
This would be true at any other f/stop, except for f/1.4, which the f/1.8 will not have. How much of a stop difference is there between 1.8 and 1.4? One fourth of a stop? Less? More?
The 1.4 lens will let in slightly more light, wide open, than the 1.8 lens. There's really not much difference. Is that difference worth $200 more to buy the lens (used)? I have a 1.8 lens and rarely use it wide open. It's also smaller and lighter.
GCasey wrote:
I won't claim to be an expert on depth of field, but seems to me that if both the f/1.8 lens and f/1.4 lens are set at f/4.0 each will have the same depth of field, no matter which manufacturer made the lens.
If the camera is the same, actual focal length is the same, the subject distance the same, and the f-number the same, then yes, the DOF will be the same regardless of type of lens, so long as both lenses are capable of the same f-number.
But that is not what is meant by "outperform," per my previous post.
This would be true at any other f/stop, except for f/1.4, which the f/1.8 will not have. How much of a stop difference is there between 1.8 and 1.4? One fourth of a stop? Less? More?
If the f-numbers are *exactly* f/1.4 and f/1.8, then there is a difference of 2 Log[2, 1.8/1.4] = 0.72514 stops. But since these f-numbers are presumably rounded from a 1/3-stop scale (i.e., f/1.4 is actually f/2^(1/2) and f/1.8 is actually f/2^(5/6)), then the difference is actually exactly 2/3rds of one stop.
2/3rds of one stop represents approximately 58.74% more light-gathering ability (one stop is 100% more light gathering ability).
The 1.4 lens will let in slightly more light, wide open, than the 1.8 lens.
If by "slightly," you mean 2/3rds of one stop, or 58.74% more light, then yes, I suppose that is correct.
There's really not much difference.
Some people gladly pay several thousand dollars more for a lens that shoots f/2.8 instead of f/4. "Not much difference" is subjective, but 2/3rds of a stop is significant to me when every bit of light counts.
Is that difference worth $200 more to buy the lens (used)? I have a 1.8 lens and rarely
use it wide open. It's also smaller and lighter.
If you don't use it wide open, then that's your choice. That doesn't mean nobody else does, or that the need does not exist. How you use your tools does not necessarily reflect on how others do.
Isn't this the basic question raised by the OP?
Not really. There are other differences that were explained in my previous posts.
justruss wrote:
Oh, and I would add that the above is in reference to roughly 24mm to 85mm, where there tend to be lenses with ultra-wide apertures @ f/1.4 as well as 1.8, 2.0, and 2.8.
When it comes to longer lenses, where f/2 is as fast as it gets (200mm), and f/2.8 is usually very fast (400mm), the value of wider apertures-- primarily with moving subjects (sports/birds)-- in order to get more light is dramatically increased, IMO.
There's also F .95, 1.0, and 1.2.
And Canon makes/made a 200 F1.8.
And to touch on an earlier post by someone, no-one brags at F1.4. Bragging rights begin at F1.2. :P
Another reason is most lenses don't perform nearly as well "wide open" as they do stopped down some. So if you buy a f/1.4 lens, it will usually be much sharper with better contrast at f/2.0. If you buy a f/2.0 lens, it won't perform as well at f/2.0 as the f/1.4 lens will.
wickerprints wrote:
Well, your message certainly comes across as being distasteful to me. I don't like your implication that "professional = good/knowledgeable" and "amateur = bad/ignorant." It feels elitist and it also implies that you think that only amateurs shoot wide open because they think "hey, what else did I buy the lens for," not "I'm shooting wide open because I that is the best choice for what I want to do."
Professionals absolutely DO shoot wide open and they do it all the time. Weddings, sports, portraits.
I prefer to think that photographers fall into two basic groups--those who shoot what they need, and those who shoot what they want. The former shoots to get something they can use. The latter shoots to achieve some desired effect. Some photographers are both, depending on circumstances. Personally, I'm going to shoot at whatever aperture I damn well please depending on what I want to do, and that does not make me any less skilled or knowledgeable or capable for it. I certainly don't need someone to come around and make sweeping generalizations about the intent behind shooting wide open and what that might say about one's photographic experience....Show more →
I apologize if it came out that way... hence my followup post explicitly saying that I'm not trying to knock non-professionals. Hell, I'm not even implying that professional = better (however you/I/whomever personally measure better).
Amateur doesn't mean ignorant. But I think that amateurs actually lust after and shoot super-wide aperture lenses wide-open more often than professionals, particularly professionals that I consider to be at the top of their game (which is a very subjective thing, hence why in my earlier posts I also, explicitly said this before).
And I also explicitly said I was focusing in the f/1.4 vs. f/1.8 comparison, which is what the OP asked about. Not f/2.8 vs. f/4 or f/2.8 vs. f/1.x. I shoot both professionally and for myself, and even then I see a difference in what I lust after and how I shoot in those two different situations-- and I'm definitely not angling to call myself ignorant (whatever anyone else thinks about me ).
There's no question-- and here it's not just supposition like it was when I was addressing what "I think" would be the case-- that when I'm shooting professional jobs (and they've ranged from weddings, commercial, corporate event, catalogue, and mainly now photojournalism) that I far more often than not am focused on getting enough in focus not reducing my dof when I'm shooting in the f/1.4 to f/2.0 range. Yeah, if I choose to shoot at f/2 instead of f/8, it may be for compositional/dof reasons... but that's not what the OP asked about, and that's not what I was addressing.
I reckon that for most of us f1.8 will do nicely. There are applications that do benefit from f1.4 or f1.2, but if you are a photographer needing such fast apertures believe me you will KNOW from experience you need them.
I'd start off with f2 or f1.8 lenses, and only stump up the money for faster glass if it turns out you need it, for example you like shallow depth of field, or focussing in low light etc etc.
Speaking entirely personally I need fast wide glass (f1.4) for night photography, but in the daytime my f4 zooms are entirely fast enough.
I have the Canon L 35 1.4 and 24 1.4 II. I really like working with both of these primes. I think the design of the 1.4's from both Canon and the new 35 and 24 Nikon 1.4's is superior to the lens designs in other lenses. When you shoot with one you can feel and see the difference between these and the kit lenses or even the similar focal length F2 or 2.8 lenses in color rendition and bokeh.
I previously had owned the 85 1.2 L but didn't find it as useful to me as these other lenses so I sold that and opted for the 85 1.8 which is a very good non L piece of glass.
Richard Nye wrote:
Another reason is most lenses don't perform nearly as well "wide open" as they do stopped down some. So if you buy a f/1.4 lens, it will usually be much sharper with better contrast at f/2.0. If you buy a f/2.0 lens, it won't perform as well at f/2.0 as the f/1.4 lens will.
I did not read through the whole thread, so some may be repetetive.
first off, a 1.4 lens usually would perform far better at 1.8, than a 1.8 lens. second, with a wider lens (35, 24) 1.4 is not that shallow, if your subject is not very close. third, I routinely use my 85 1.2 at 1.2, and it is fantastic for subject isolation. it is not great for shooting a head shot at 1.2, but fully body shots, or even half, great. fourth, there are times that you really need the extra speed. When we went trick or treating, I put my 35 1.4, and still was shooting at iso 6400. I also shot video footage, which I could not have with a 1.8 lens. just not fast enough. fifth, a lot of times, the difference is not simple aperture. the faster lenses often may have better color and contrast, or nicer bokeh, b/c they are higher grade lenses.
hope that helps.
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