I think I just got my first good lens

[justiceischeap]

I ordered a 12-24mm f/4 used Nikon (got a great deal) and the mail lady just delivered it. *Happy dance*

I'm learning a few things about my camera (d5100)--I'm not at all happy with the auto-focus feature. It seems to leave images very soft (no matter the mode I use). I've started playing around with manual focus and I'm improving the sharpness by using live view and zooming in for the focus.

Anyway, I slapped the new lens on the camera and man, is it WIDE! The lens was about 2 inches from Kid Robot there (the reason I have him on my laptop, and my screen angled down is 'cause the lighting in my house sucks--hence, the use of the atrocious flash that I couldn't bounce cause I was focusing). Anyway, not only is it wide but it's pretty darn sharp too.



I think I could get addicted to good glass.

[nadinbrzezinski]

1. If you have an F-stop on the lens

Go manual..

The kit lens does not have the settings. So for that I use aperture priority. Why it seems "soft"

I am impressed with the kit lens though. I have gotten very good shots under very difficult conditions for the paper, night, fire engine on a road with quite a bit of smoke.

When using the other two lenses I play with manual and f-stops.

Here, te article with the photo

http://www.eastcountymagazine.org/node/10676

[justiceischeap]

2. I don't have f-stop on the lens

But generally, I've been using aperture priority mode and still get softness (I also wear glasses and have a hard time with the viewfinder so it could be me). I guess I'm searching for that "tack sharp" shot that all pro photogs talk about and when I enlarge the images, I'm not seeing that. When reduced for the web, they're sharp enough but if I wanted to print a shot, I worry about the sharpness in larger prints.

That's a nice shot you got in that article, were you hand-holding?

[nadinbrzezinski]

3. Hand holding and using the truck for a brace

Took five tries to get a usable shot.

[Major Nikon]

4. Here's a bit of information which might be helpful

Understanding your focusing systems is the key to getting sharp pictures. Your camera actually has two independent auto focusing systems. While in live view, your camera focuses on what the actual sensor sees. You also get the box which shows you which area(s) your camera is evaluating distance information for use in focusing. The down side to live view is the autofocus is slower, but you get some neat features like face recognition in return. When you are not in live view, your camera is using distance sensors which are independant of the sensor, so effectively it's a completely different autofocus system. When you're using the normal autofocusing system, there are several different modes which you can pick from. It's important that you understand how those modes work in order to insure the camera is focusing on what you intended.

Another thing that's important to understand about autofocusing systems is they need contrast in order to derive distance information. Trying to focus on a subject which is large and has very little contrast can confuse the autofocus system and this is especially true in low light situations where contrast suffers. It's important to understand the limitations of your autofocus system. Knowing when to switch to manual focus mode is invaluable, but has it's own limitations because your eye also needs contrast to determine focus. I use manual focusing fairly often, so I replaced the stock prism screen in my Nikon to a split circle like many older film cameras had.

I don't have the Nikon version of this lens. I have the Tokina which is optically very similar. One thing you're going to find about this lens is a strong tendency for flare and ghosting which is typical of ultra-wide lenses.

[justiceischeap]

5. So much helpful information!

Thank you for taking the time to write that out. I'm pretty happy with my 18-55mm kit lens and I have a 50mm prime that I like a lot (takes really sharp photos) and now this lens. I guess my biggest disappointment is my zoom (it's a Nikon 18-200). No matter what I do, I can't seem to get tack sharp photos with it. I've tried it in lots of situations (even not using it at 200mm) and I just can't seem to get sharp images. I used auto-focus and I get the green box in live view, I use the viewfinder and get the green dot in the left-hand corner and even in manual, when I'm showing the green dot, the images still aren't sharp. I bought the lens used from KEH, so maybe it's bad.

[Major Nikon]

6. I have the Nikon 18-200

If you want to test the autofucus accuracy, turn all the VR functions off and put your camera on a tripod. Set the lens to around 70mm and f/8. Focus on a high contrast subject that you can easily evaluate focus that's about 15' away in both live mode and without live mode. A piece of paper that's half white and half black works well for this or a piece of paper that has a thick black line running down the middle. The idea is you want something flat that has lots of contrast. The two results should be identical or extremely close. If not, the lens may have a focus problem and you may need to send it in for service. I test all my lenses this way.

I think it's a wonderful lens, but it's important to understand its limitations. This lens is going to be at its sharpest from around 24-100mm focal length and around 1-2 stops down from its maximum aperture, although it does perform surprisingly well at 18mm it suffers greatly at the long end. I'm just guessing here because I don't remember the exact settings where this lens performs at its best. I generally only use it a stop away from f/8 and less than about 125mm as a general rule of thumb. I will use it outside those extents, but I am aware of the limitations this creates in performance and knowlingly accept the tradeoffs.

Here's a link to my Flickr page where I compare the 18-200 with several other lenses I own. You can do your own tests and see how well yours stacks up to mine. At this focal length and aperture, this lens compares quite well to my 70-200, which cost around $2K at the time I bought it. Naturally the 70-200 is going to be able to do things this lens can't, but it just shows how well the lens performs at its optimum settings.

The 55-200 also does quite well and it's a kit lens. These pictures are cropped, so don't try to match the framing. The focus distance was around 10-15' IIRC.

http://www.flickr.com/photos/62788945@N08/sets/72157626572470855/detail/

[justiceischeap]

7. Do you have the first or second version?

Probably be helpful to know that when I set-up the tests to make sure we're comparing the same lens. Mine is the first version. I believe I'd read that the first was sharper than the second and that's why I hunted it out.

Edited to add:
Thanks for the info on how to test the lens and letting me know its "sweet spot" for testing.

[Major Nikon]

9. I have the 2nd version

Optically I don't think there's any difference between the 1st and 2nd version. Both have 16 elements in 12 groups. Both have identical MTF curves. The differences are mainly in the electronics and the addition of a few features.

[justiceischeap]

8. Just wanted to show you this

I took this today on top of the local parking garage (I wanted to see how wide "wide" is). I was pretty much shooting into the sun, had my lens hood on and this is the result.



Obviously it's blown out where the sun is but I'm not seeing any residual ghosting or flares. I have a skylight filter on it that the camera shop included when they shipped it, don't know if that and the combo of the lens hood saved me or not.

[Major Nikon]

10. You won't see ghosting or flare most of the time

It's just something to keep in mind because you will run into situations where it's going to happen. Filters may actually exacerbate the problem depending on which filter you're using and in what situation, but keep in mind that these effects can also be used creatively so they aren't always a bad thing.