I know there are lenses like f/0.7  However as a beginner I'm wondering what's the barrier of making ultra fast lenses like f/0.01 ?  Also if lens manufacturers willing to make wide aperture lenses, why it become more expensive? What factor makes it more costly?
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has a maximum f-stop value of 2.8. I've held it in my hands, it's a big lens. Meanwhile,  can go up to f/1.2, despite being 25% cheaper and a LOT smaller. So at least with these two lens, there is not a very direct correlation between price and f-stop ability.  What is it that determines a given lens' f-stop range? Why can't that 105mm go sub-2?
117985
I read following in a web site ()     Lenses with maximum apertures of f2.8 allow the camera to use all high   precision sensors. In low light or other situations that are hostile   to autofocus, that’s a big deal. Lenses with a maximum aperture of   f4.0 use only the center focus sensor in its “high precision” mode,   and use the other sensors in their “horizontal line” only mode. Lenses   with a maximum aperture of f5.6 use all sensors in their   “horizontal-only” mode, and lenses with a maximum aperture of f8 use   only the center sensor point, and that with horizontal sensitivity   only.   I want to understand if this is completely true? I am raising this because recently I have purchased a Nikon 70-200 f/4 lens and would like to understand if I have made a wise investment, or, should I collect some more money and buy a 70-200 f/2.8 VR-II lens.
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You probably know Scott Schuman and his blog (). What kind of lens (that is not expensive) would you recommend for Canon 550D to achieve similar effect (in terms of DoF etc.)? I'm a newbie so I'm not sure how to properly interpret those photos' EXIF info. My guess is, that a similar effect can be achieved using .   PS:   Update: Thank you guys for all the answers, it's much more clear for me right now. I think I'll try the Canon 50mm f/1.4 lens.
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We have a question and answers outlining the . I'm interested in the other DSLR makers, and how the cameras they make compare in terms of significant features, system design philosophy, and unique or interesting photographic capabilities enabled or made easier by these cameras. Likewise, what such things are not handled as well?  Take "the big two have more market share" and the associated advantages of availability, accessibility, and third-party support and documentation .  I'm not interested here in compact cameras, interchangeable-lens cameras with electronic viewfinders, or in rangefinders. (If you're interested in that, though, see )  P.S.: Differences in lens lineups are covered at
51999
Lightroom has Lens Correction tools such as Distortion, Vignetting, Chromatic Abberation, etc. depending on the brand and model of lens.  Due to this feature, is it less relevant what the distortion quality is of lenses because Lightroom can correct them?  I understand a perfect lens is always better, but since it can save a huge amount of money, maybe the expense is not worth it?
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I have a Canon 550D which I've been using for around a year now. I really love it and have learned a great deal with this and the 18 - 135mm kit lens. But now with experience I feel the need to get some better glass. I won't be buying a new body any time soon because I figure investing in some good glass is more important.   As I have looked around, I see quite a few good used L lenses I can get in ebay for good bargain prices. But I know that the EF lenses don't have the same focal length in the cropped sensors. Is it a wise decision to buy these EF lenses or buy the cropped sensor alternatives?  I have the following lenses in mind that I am looking to buy down the line from the canon range over the next several months.  16-35mm f/2.8L, 24-70mm f/2.8L, 70-200 f/4L.  Are these apt choices for cropped sensors? I know most pros with FFs use these but I am a bit skeptic that they will serve the same purpose for me. If so what are the alternatives for this that have almost as good image quality?
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I've bought a  to use with my EOS 200D and while I love the wide aperture, it appears to be quite difficult to achieve sharp focus on people's faces when shooting at f/1.8. I've tried both using Dual Pixel focus in Live View and using the center focusing point in the viewfinder, but it doesn't get me perfect results.  Is this simply a characteristic of cheap wide-aperture lenses? Or is it impossible to get sharp focus with a fully open aperture?  When I'm at at home using a tripod and focusing on a still subject I do get good focus (so it's not a camera or lens issue). But it's hard to do with people who are slightly moving between shots.
67067
I'm just trying to decide which new lens to get. I need to take surf and windsurf photos from onshore. Sometimes 300 mm is enough but there are many times they are too far away. I have a sigma 70-300 but I need something better, if the light is not perfect it doesn't give me the sharpness I hope for. I can not afford the 400L 2.8 of course, so I'm trying to choose between the Canon EF 100-400L, Canon EF 70-300L (which I heard is far better than the base one), or Sigma 50-500. My body is a canon 600D.
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I am looking at trying to buy a long range lens for shooting animals and nature. I'm kinda new to photography and am not sure which brand or size I should be looking for. What features are important and what will I get from different price points? I also would like to get a macro lens for really close shots — is that possible with the same lens?  I have a nikon d3000.
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Now that I am finally getting a fast zoom (Tamron 17-50mm 2.8) I've been considering a fast prime to go with it, specifically a Sigma 50mm 1.4. Despite its shortcomings, it still does really nice subject isolation past f/2, which is important to me. I was wondering if it might be redundant since my zoom is already a pretty fast fixed aperture. Of course, 1.4 is two stops faster than 2.8, but as with all primes you have to stop it down to get sharp results.   The main thing I am worried about is that if I drop $500 on a Sigma, it won't get used because there is already something O.K. in that range. Basically, is two stops difference enough to make you want to switch lenses?  EDIT: Perhaps I should add and as may have already been mentioned, these $500 could go to a nice speedlight which could sove the low-light 'issue' you get with f/2.8 vs f/1.4.
111662
I am wanting to venture into some extreme macro photography, specifically insects, such as . After doing some research I have believe that my 1::25 macro lens will be sufficient if I am to use some extension tubes (which I have bought).  I would like to shoot the in the wild, is this possible/likely? Or is this always a catch, then release style of shooting?  Regarding the link I've posted, would this be possible with a 1:25 macro and extension tubes? I have a set of three (21mm, 31mm and 13mm). How would you go about shoot a blue bottle for example? Surely they are going to fly away? Should I use a tripod or will that cause more of a hindrance than a help? Are there any techniques/tricks I could use to get a sharp focus on my subject?
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I made a series of outdoor shots with Nikon D5000, with the 18-55mm 1:3.5-5.6G VR kit lens.  On some shots, I see in the EXIF info f/11, and in another shot, f/9.    How can that be, that the f-number is greater than 5.6, when that's listed as the maximum in the lens spec?
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I have the Nikon kit lens that came with a D5100 — the kit lens is  . I was thinking of getting a fast lens and I am looking to buy the .  Should I consider 35mm or instead buy a 55-200mm for better range?
9144
Is there such a thing as a maximum aperture that a lens can be open to?  What about a minimum aperture that it can be closed to?  Do these concepts even make any sense?  Is there a lens with the narrowest aperture in the world?  Is there one with the widest?
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I'm currently looking for a wide angle lens for my Canon T3i. I would prefer a prime lens. I want to use a wide angle lens primarily for video (so the lens needs a quiet AF motor) but for still photography as well. One thing I don't want in a lens is photos/videos that result in a major fish eye effect. It will have to be an EF mount for my upgrade soon to the 70D. Budget $350  Your input would be appreciated.
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I am thinking about purchasing a Canon 60D and selling my Rebel XT and wondered if I would need to purchase new lenses? I only have two but as you all know, once you invest it is hard to not take those into consideration when purchasing a new camera.
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My girlfriend owns a D5100 and I own a D7000 for which we both share lenses (or try to when appropriate). I own the 18-55 kit lens, a Nikkor 50mm 1.8g (I may consider buying the inexpensive 50mm 1.8d so that we can both have the 50mm at all times) and a cheap Sigma 70-300 4.5-5.6.  As of right now, I do 65% of my shots using the 50mm, including, most of the time, landscape photography. I just adjust the composition by adjusting my position and only use the kit lens when that's not an option. For some time I've been thinking about acquiring a wide angle lens, but after checking up the prices and different models I couldn't make up my mind.  What is it that you look for in a wide angle lens?  To make it easier to explain where my doubts lay, let's say the Nikkor 24mm 2.8D which sells on amazon for 360 pounds / $450.   Do I really need a fast lens for landscape? I mean, 90% of my shooting with a wide lens is going to be architecture or landscape so why would I need a fast lens? Most of my photography (which tends to be street photography and portraits) is taken with the 50mm or the telephoto (which I'm seriously considering upgrading to something not crappy)... are there other usages for wide angle (other than landscape and architecture) that I'm missing? (I mean things you'll do often, not things that you may do but you never end up really doing). How is it different from the kit lens? I can deduce build quality of the kit lens is not going to be great, but it's still a 18mm f3.5 in the wide side, so wider and reasonably fast... is it really worth it to get the Nikkor 24mm? Why?