What to look for in a wide angle lens?

Question

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?

Answer 1

For landscape photography the advantage of most prime lenses over kit zooms is not the maximum aperture, it is the sharper image it can produce at middle apertures (i.e. f/4-f/8) and better performance in the areas of distortion, vignetting, and chromatic aberration. While you can correct for those in post, you do so at a price of maximum sharpness.

Traditionally a lot of street photography has been done using 35mm lenses and 35mm film. That field of view equates to 23mm with your APS-C cameras. The wider aperture of a prime lens allows shooting earlier in the early morning twilight and deeper into dusk. The image quality concerns mentioned above in relation to landscape photos also apply, although distortion is not generally as big an issue for street photography.

There are also other use cases that will take advantage of the faster aperture, night sky photography being the most obvious. While that might not be a use case that you would ever consider there are many users of such lenses for which that is the primary focus of their photography. Just as you like to do street photography and portraits, those use cases may be ones which others would consider things they might one day do, but never end up actually doing.

Answer 2

Well, first, a f/2.8 lens is not that fast, especially for a prime.

In general, a (correct) prime will yield a better image quality than a zoom (usually, although for example a "pro" grade zoom would outperform a "lower" grade or outdated prime).

Now let's look at your questions :

• For your first question, I won't dwell on the pros and cons of fast wide angle, you can look at the related link suggested above.
• For your second question, wide-angle can give photos a very different style (distortion, emphasis on the foreground in a vast background...), but since your cameras are DX format not FX, the 24mm will behave more or less like a 35mm, hence diminishing these effects.
• Third question, comparing to the kit zoom you already own, even admitting the aperture @ 24mm is f/4, you'd gain only one stop. That's not much, especially with the D7000 that has good low-light performance. I don't know the relative build quality of these specific lenses, but indeed kit zooms are usually lower quality (optical, build, etc.).

Did you consider cheaper alternatives (but less "evolved" : manual focus, manual aperture) like Samyang (so that you would not regret buying a lens for a "once in a while" use) ? Or upgrading from your kit zoom ?

Answer 3

When looking for a wide angle lens you should consider a few very important things:

• Focal length
• Image Quality
• Maximum Aperture
• Focus modes (AF/MF)
• Filter compatibility
• Feature set (FTM, IS, USM, etc.)
• Mount
• Weight, size, cost, etc.
• Intended usage
• Distortion & Projection
• Flare resistance

Most of the above is not uniquely important to wide angle lenses, but the items in bold I would suggest are of particular interest to wide angle lenses.

Focal Length

Focal length is of utmost importance when considering a wide angle lens. If you want to shoot indoors and you can't simply back up your body, you may require a 17mm lens for a shot. Yes you can stitch images together if desired or necessary but you may want to buy the focal length that best fits your desired output to begin with(See: Do you still need an ultra wide angle if you can now stitch images?). There are many online visualization tools to determine what an image looks like at various focal lengths, I would encourage you to check them out first - but ultimately the best way to determine the right focal length is with some first hand experience using them. Finally, as you go wider distortion will certainly bear its ugly head. More expensive designs will help the situation but it is safe to say that wider lenses will typically experience more distortion. See this question for more information: How much does 1 mm get you in a wide-angle lens?

Aperture

The practical difference between f/2.8 and f/1.4 is for most situations identical with a wide angle lens as with any other focal length. The advantage of f/1.4 vs f/2.8 is that you will be able to shoot in significantly darker situations, or in the same situation with either a faster shutter speed or lower ISO value. It also gives you greater control over depth of field and the ability to create shallow depth of field images even at wide focal lengths. These are very wide apertures for any wide angle lens. Most wide angle lenses are actually quite a bit more narrow in the aperture area. See this question for more information on why: Why do wide angle prime lenses have relatively small apertures?

Filters

Filters are somewhat unique to wide angle lenses as some very wide lenses(especially fisheye) do not have the ability to use screen on filters. If you want to use filters(ND, Polarizer, etc.) you have to take this into consideration. You may have to either buy a new filter system or not use one at all depending on what you desire. Further you have to consider the impact of using a polarizer with a wide angle, as it can produce poor results.

Overall

Overall, the two lenses that you described are most importantly different because of their focal lengths. I personally would not be using them for the same types of shots as the field of view is so different. If you demand very wide apertures(astrophography, portraits indoor, etc.) you may also benefit from the wider aperture but that is a personal decision.

Additional Resources:

• Do I really need a wide-angle zoom lens?
• Is image stabilization a necessary feature for wide angle lenses?
• What to look for when testing a wide angle lens before buying?
• How do I compare two prime lenses of different focal lengths?
• What to look for in a wide angle lens?
• What filters will work with an ultra wide angle lens (for landscape)?
• Is it wise to use polarizing filters with wide-angle lenses?