Is the difference between f2.8 and f4 significant in a lens?

<p>I've been looking at a couple of lenses for street photography. I want a good zoom lens that covers an ultra wide to wide/normal focal range. Nikon has a newer 16-35 f/4 G lens for less money than their classic 17-35 f/2.8 D lens. Same goes for their 70-200 f/2.8 which is now available in f/4 constant aperture. I don't really shoot action or sports at all, but I do shoot indoors, night, and low light on occasion. Is the difference between f/2.8 and f/4 really significant to warrant the extra money? Is f/4 still considered a 'fast' lens? Thanks!</p>

<p>2.8 lens transfers twice as much light as the f/4 lens. So, it doubles amount of light that you could possibly need in dark places.<br>

Modern DSLR bodies allow good performance at high ISO, so use of slower lenses makes ecomonical and practical sense.</p>

<p>f/4 is not considered a fast lens.</p>

<p>Since you shoot indoors, and low light, the 2.8 lens is a better choice for you.<br>

If you have top ISO performing DSLR, so f/4 could be good enough for you.</p>

<p>What camera do you use ?</p>

<p>Thanks Frank. I just bought a Nikon D600, so it has good high ISO performance. </p>

<p>For street photography, you often want good depth of field so that the entire scene is rendered in a realistic-looking manner. This being the case, fast apertures are not that important. If you're shooting at f/5.6 or f/8, it really doesn't matter whether the lens can go to f/2.8 or only to f/4.</p>

<p>But for night or indoor shooting (without a flash, I assume), if you want (or at least are willing to accept) shallow depth of field, then f/2.8 might come in handy, since one stop wider aperture means one stop faster shutter speed or one stop lower ISO.</p>

<p>I wouldn't consider an f/4 lens to be "fast" by today's standards, but what matters is whether it's fast enough to suit your purposes.</p>

<p>Another aspect to this question is that an f/2.8 zoom will be larger and heavier than an f/4 zoom. How much weight are you comfortable carrying?</p>

<p>Last year, I splurged on a 24-70 f/2.8 Nikkor which I love, but it is heavier and feels unbalanced on my D600. It's a good focal range for street photography (I like to get in closer and capture more environment), but it's an intimidating lens (especially with the hood) and heavy like a tank. I use it mostly for portraits, but not practical on the street. Nikon recently introduced a 18-35mm f/3.5-4.5 G which has had good reviews, smaller, lighter, and less expensive compared to other zoom lenses in it's focal range. Maybe with the good ISO performance on my D600, I can still use it for low light. </p>

<p>Have you considered a fixed lens like a 35mm? It's light, small and good for street photography. You can get fast aperture 35mm lens but that would add more weight and size and as someone already mentioned, you'd want to st it at f/8 or so for more depth of field.</p>

<p>As Frank said, going from f4.0 to f2.8 is one stop, which would allow you to double your shutter speed, say go from 1/15 to 1/30 second. It will reduce camera shake or motion blur. Maybe enough to give you a keeper, if you're just on the edge of having a manageable shutter speed, or not.</p>

<p>OTOH, the faster lens can be significantly more expensive. It might also be a little less sharp, even at the same aperture. It's just more difficult to manufacture a faster lens, <em>and</em> keep it as sharp. It's inherently harder to keep the curvature of a larger lens accurate. And wide open, the faster lens is <em>very</em> likely to be softer.</p>

<p>It will also have reduced depth of focus when wide open. Not necessarily a bad thing, sometimes sought after, other times frustrating.</p>

<p>The faster lens will invariably be bulkier and heavier. A good example is the Canon 70-200 f2.8 vs f4.0. The former is roughly double the weight, about an inch or so longer, and has a larger filter size (albeit a very common filter size).</p>

<p>Also, the faster lens may sacrifice features to avoid the price getting completely out of reach, and/or avoid the weight increasing even more. For example, the Canon f2.8 24-70 zoom does not have Image Stabilizing, while the f4.0 version does. IS will gain you 3~4 stops for camera shake, but does nothing for motion blur of your subjects.</p>

<p>So, many factors. ;)</p>

<p>Whether it is a significant difference depends entirely on what you shoot. For low-light work, it can be, for two reasons. First, on many cameras (I don't know Nikons), there is at least one AF point that is more sensitive at f/2.8, giving you better AF in low light. Second, it saves you one stop in ISO, hence giving you less noise. On the other hand, depth of field is smaller at f/2.8, which may or may not be a problem for what you shoot.</p>

<p>However, you have the answer in your hands. You say that you have a 24-70 f/2.8. Shoot with that lens at f/2.8 and replicate each shot at f/4.0. That will tell you the answer.</p>

<p>Is the difference significant? Yes, both in terms of available light and depth of field.</p>

<p>Do you need f/2.8? It's definitely helpful, but for the vast majority of photos, you can get by without it.</p>

<p>f/2.8 lenses tend to be significantly larger and heavier than their f/4 counterparts.</p>

<p>In terms of actual lenses, some f/4 lenses are very sharp and some are less impressive. The same can be said for f/2.8 lenses. The aperture doesn't tell the whole story, so evaluate each lens on its own merits. For instance, Canon's 70-200 f/4L IS lens is very sharp. I have heard good reviews of Nikon's 70-200 f/4 as well, but I haven't tried it myself.</p>

<p>A lot depends on your lens too. I have a few lenses that are soft wide open, and don't really sharpen up until F4 or even F5.6. Some are tack sharp wide open.</p>

<p>I think the best way to determine whether the extra lens speed makes a difference for you - particularly since you're shooting indoors - is to try using a fast fixed-length prime. The Nikon 50mm f1.8g runs a couple of hundred bucks and will show up the difference a fast lens gives even more. Much smaller, lighter and comfortable handling, and much less intimidating on the street.</p>

<p>The new issue of Popular Photography has an article on f/4 compared to f/2.8 lenses. F/4 lenses are smaller, lighter, and less expensive than comparable f/2.8 lenses. Also with stabilization and with today's cameras having such good image quality at high iso's f/2.8 is not as important as it used to be. If you are not shooting indoor sports you may not need f/2.8.</p>

<p>My recommendation is to stick with the constant F/4 and use the savings in cost and weight for a single prime, faster lens (ie. 24 or 35) or even a 50. I shoot Canon, so am less familiar with the Nikon lenses. But I have a Canon 50 1.4 that is both cheap and quite good. For the record, I also have a 17-35 2.8 lens, which I bought used.<br>

If I am shooting with my 5D3, in most cases, in low light, I will still try to shoot at f/4 even when I can go lower. But that is possible due to the better ISO performance of modern cameras (fyi the 5D3 is supposed to be particularly good in this regard).<br>

With Canon at least, one can buy the f/4 wide zoom + faster (non L version) wider prime or nifty fifty for a lot less than the 2.8 L wide to normal zoom. <br>

In my experience, I find my shots with the 50 are more enjoyable as I put a lot more thought into composing those images as I loose the zoom ability. Just food for thought!<br>

If I were a professional (ie. getting paid for my images), perhaps I'd feel differently. But since it's just a hobby for me . . . </p>

<blockquote>

<p>I've been looking at a couple of lenses for <strong><em>street photography</em></strong>. I want a good zoom lens that covers an <strong><em>ultra wide to wide/normal focal range</em></strong>. I don't really shoot action or sports at all, but I do <strong><em>shoot indoors, night, and low light on occasion</em></strong>. Is the difference between f/2.8 and f/4 really significant to warrant the extra money?</p>

</blockquote>

<p>With respect to what you want to do: most of the <strong><em>significant differences</em></strong> between F/4 and F/2.8 will be when you are ‘<strong><em>indoors, night, and low light</em></strong>’. As you have mentioned it is only occasionally that you are in these shooting scenarios and this is the main point of your question – is it worth the money for only one extra stop of lens speed for those odd periods of time.</p>

<p>Looking at your question another way, I see one salient point: IF there ever is a <strong><em>significant difference,</em></strong> then that difference will be <strong><em>significantly reduced</em></strong> with an F/1.4 lens.</p>

<p>To this end, a 24/1.4 or 35/1.4 would be worth considering down the line, as an addition to the 17 to 35 F/4 zoom which you are considering now. But we are talking much more money going that route, obviously.</p>

<p>When shooting people indoors, a lot of the time you'll be likely <a href="/photo/16011795&size=md">shooting tighter: and that's when the Depth of Field <strong><em>difference</em></strong>, is more significant.</a></p>

<p>The other point which, to my mind sticks out like a pimple on a pumpkin is: if "street photography" means "street portraiture"- then there will be a very significant difference apropos Depth of Field, between F/4 and <em><strong>F/1.4</strong></em> - and that is why a very fast 35mm Prime Lens (on a 135 format or "full frame" camera) is so popular for <a href="/photo/16814634">Street Portraiture</a> and as a <a href="/photo/16977107">general use Prime when "a fast lens" is ever required</a>.</p>

<p>WW</p>

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