Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax Lenses

Reply
 
Thread Tools Search this Thread
Old Jul 17, 2010, 11:06 PM   #11
Senior Member
 
NMRecording's Avatar
 
Join Date: Feb 2010
Location: Eastern Appalachains
Posts: 866
Default

I just went through this focal range maze a month ago.

I looked at the

pentax 12-24, 16-45, 16-50
Tamron 17-50
Sigma 17-50
sigma 24-60
sigma 10-20
and the Tokinas

I ended up having a hard decision between the Tamron 17-50 and the Sigma 17-50. These lenses seemed to have the best overall performance for the price range.

It appeared the Pentax DA* lenses seemed to perform better than these two in shown results but the price on these lenses are double the Sigma and Tamron

So which one did I get?

The Sigma 24-60 EX DG. Ive heard of some back focusing problems but it seems Sigma backs their products and fixes them easily so I took the gamble. This lens has been discontinued but I got it for a great price. In reviews, I have read it was sharper than the sigma 17-70.

I too wanted an extreme to medium range zoom range and like the others mentioned they dont exist, and if they did they most likely wouldnt be very good lenses. The amount of distortion in a lens trying to cover that would be phenominal or else the price would be. For 250.00 I think I got a real nice bargain lens with 2.8 aperture throughout and this lens is incredibly sharp. My next lens is going to cover the extreme wide angle lens, perhaps being the pentax 12-24.


The Tamron 17-50 seemed to perform better at the wide end and the Sigma 17-50, the long end. The Tamron was sharper corner to corner but Sigma seemed to have punchier color. The Sigma 24-60 seemed to have the throughout sharpness of the Tamron 17-70 and is even sharper at wide and has beautiful coloring. I realize its not as wide as you may want but still shoots very wide and is nice for a walk around lens, landscaping, architecture, portraits, and group shots. It does not have the HSM so even though its 2.8 throughout the auto focus supposively isnt as fast as the Pentax da* but its good enough for me.

The 24-60 also has extreme close focus so while its not labeled as a macro, or even advertised to have macro capabilities, it is still good at getting them.


I havent tested as much of the extreme wide lenses, but hopefully this info helps.



Good luck with your hunt, let us know what you end up getting, and show us pics!

Last edited by NMRecording; Jul 17, 2010 at 11:21 PM.
NMRecording is offline   Reply With Quote
Old Jul 19, 2010, 10:56 AM   #12
Senior Member
 
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381
Default

Good Morning - A wide angle lens with some range, is somewhat of an oxymoron. As others have posted, wide angle lenses tend to have a much narrower range that other focal length areas (normal, telephoto, etc.). This is due to the design of the lens, where it needs to pull in view from the edges, and even more important keep distortion to a minimum. This is pretty difficult. As the focal length increased (telephoto), you are essentially doing the opposite - in that you are concentrating on the center magnification, and shedding the edges.

The other thing is the sensor size. With the smaller APS-c sensor which is smaller, it tends to narrow the field of view, as demonstrated by the crop factor - which is great for the telephoto end - a 100 mm lens on the APS-c sensor has a field of view of a 150mm lens on a full frame sensor. This acts in the reverse direction for wide angle and ultra wide angle for the APS-c sensor size. So bottom line, for the smaller sensor - you need to work harder in the design, to get the angle of view that the full frame film had.

One small benefit on the wide angle end, is that - since the lens design is actively pulling in light and view, say for an f4 lens, I feel that it tends to feel brighter and faster. Telephoto on the other hand is taking a much smaller view, amplifying it (magnifying), so what ever you are focusing on tends to need to be lit pretty well.

Another benefit of WA is depth of field. The lens designs (due to the laws of optics) tend to have deep depth of field and relative small minimal focal distances. So, although not macro - you tend to be able to get pretty close, and have everything in focus. That is good for some things, but if you are looking for depth of field control in order to isolate your subject and have "good" blur, then WA probably will not get you there.

Pricing for this type of lens, also tends to rise - just as prices for quality telephotos rise. Why? It is an extreme - and the design and manufacturing that goes into these lenses are a bit different than a normal 50mm, say f1.7. To get faster lenses, the optics need to be larger - and that adds design, material (more if it - and high quality glass material is very expensive), construction (to hold the lenses), manufacturing (to make them). To do all of this with out a lot of induced distortion is difficult. Fish eye lenses do this very well - in that case you want consistent distortion. For rectilinear lenses, you want no distortion, especially at the edge and in the corners - and that is hard - which translates to expensive designs, construction and a lot of material.

So, in practice the wider you go, the narrower the focal length range tends to be. Normally a good focal length range is 4x - a ratio of the low end to the high end (50-200). Here, in the wide angle end - a good ratio is 2x. The kit lens from Pentax is 18 to 55, a pretty good lens. Low ends of 17 and 16 are there also, as posted already. Then you have primes of 15 and 14. Then, you tend to flip back to zooms in the range of 12-24 and 10-20. Sigma has a new wide angle lens coming out (in a Pentax mount) of 8-16.

A lot of the lens selection, tend to go hand in hand with your intended use. For wide angle shooting you tend to either do 1) landscapes and/or 2) interiors. The interiors tend to be either a) houses or b) very large interior spaces - museums or ???? The one topic that I did not identify here was people. This is because of the distortion thing. Photographers tend to shy away from extreme wide angle lenses - especially for groups due to the edge distortion - as you really do not want to distort folks on the edge, because the viewer's eye know what folks look like (the distortion sticks out) and the comparison with folks in the middle of the frame (that distortion is also very apparent). So if you want to shoot people, keep them well off the edges. So for groups, folks tend to back up more to use a more traditional focal length (18, 20, 30, etc.) as opposed to using a 10 and getting up close in the center and pulling in the edges with the lens.

The type of use tends to also define the aperture of the lens. Landscapes usually does not require fast lenses - f4 tend to be very good. Interiors are always hard no matter what. Even with fast glass - you get a stop or two, and the lens price rises very quickly - which reduces your volume (a relative low number of units sold and that pushes the price up too). So, for the most part f4. However, there are f2.8 out there. Pentax has their 16-50 f2.8 - but that too is pretty expensive (over $1,000). Tokina has come out with a 11-16 f2.8, however its not available in a Pentax mount. So for interiors, folks tend to go to the sharpest aperture (not the fastest end) and bracket - shooting HDR in order to get the resolution, sharpness, good depth of field - and overall representative lighting.

I have gone with the 12-24 and 10-17. Their field of views complement each other. The 10-17 stretches from 180 to 100 degrees, while the 12-24 goes from 100 to 60 degrees wide. The 10-17 is a fish eye, but it is pretty well controlled, and it is impossible to get 180 degrees - field of view from a rectilinear lens. So, compromise is the name of the game, here (as everywhere else).

The 10-20, as you have read has a lot of followers, and does a great job. A lot of folks say, well if your going to go wide, then the extra 2mm adds a lot. In terms of going wider, the new 8-16 I have not seen any real images from. I think that it would be interesting, but expensive, however in looking at the lens, its size is surprising small - at least from its picture.

So, there is my view of wide angle. Since others had already posted a very good overview of the offerings, I thought that this would have some benefit.


Last edited by interested_observer; Jul 19, 2010 at 11:06 AM.
interested_observer is offline   Reply With Quote
Old Jul 19, 2010, 2:10 PM   #13
Senior Member
 
Join Date: Mar 2010
Location: Holland
Posts: 105
Default

Wow interested observer, that's an elaborate but most interesting and helpful piece you wrote. This definitely increased my overall knowledge and gave me a good feel how these WA lenses work and why and how they are constructed.
The sole purpose for me to buy a WA is to do landscaping so it would, like you said, not be worth the money for me to buy a really fast lens.
You mentioned the 10-17 fisheye, but I can imagine this is more a creative/fun lens (even though you can correct the fisheye somewhat in PP) and since it has more or less the same price as the sigma 10-20 f4 that (the sigma) would be, most probably, the optimal pick for me, am I right?
I know now why theses lenses are priced the way they are, still it's quite some money for me. Do you believe I should purchase this lens before my holiday in Brasil, I can afford it but I find it still expensive, especially since I have no experience with WA and the more expensive lenses. Or would you think my 18-55 will be sufficient enough?
Yes I know it all depends on your own preferences and opinions but still

Thanks
__________________
Pentax K-x, DAL 18-55, Tamron 70-300, Sigma 10-20

Last edited by JC de Jonge; Jul 19, 2010 at 2:12 PM.
JC de Jonge is offline   Reply With Quote
Old Jul 19, 2010, 11:14 PM   #14
Senior Member
 
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381
Default

Evening JC - Well several things come to mind that I forgot to include this morning. First, before you go plunging head long into this, I think that there are several things you can do. The first item is stitching. Have you ever tried to stitch images together? I can think of no better area to try this, regardless of where you live - in the city or country. I would step outside and use the Kit lens, with the camera in the portrait orientation, and take a series of images, right to left, with an overlap of about 25%, trying to keep the movement from one image to the next somewhat level - all hand held. Then down load Microsoft ICE - its free.
You can also do multiple row stitching too. I would literally go out and photograph anything, trying this and see how it turns out. Here is a posting with an example that I did - by the way - the example link was hand held.
Now the image in the link above was made with about 24 images about 3 rows of 6 or so images each, using my 55-300 lens at about 100mm. You can do exactly the same thing using either of your lenses. Do a single row at 18mm and see how that turns out. Then try a longer focal length, 50 or 75 or 100 mm. Microsoft ICE will do a single row or multiple rows. For the price - you can't beat it...... and its easy! Also, you have everything you need with out buying a new lens. ZERO CO$T!! - you do NOT even need a tripod!! PS - I would try to use ISO 200 (for low noise and high image quality) and f8 (for best image quality - since both your lenses are at their best around f8 or so).
__________________________________

So if you absolutely insist on spending some money, here are some WA lens ideas to consider. Here is a link that has 3 different images from 3 different lenses, of essentially the same view.
Here is a link with the same 3 images lined up a bit better with some what of an improved explanation.
Actually, after a lot of playing around and experimentation, I found that the DA 10-17 FE provided exactly the image result that I was looking for (and I did not really expect that it would have yielded this result). I was trying to stitch multiple shots together trying to get the iridescent blue sky with the valley lights and mountain silhouetted. If was difficult to stitch because of the time from the first shot to the last, and as such the last row shot I lost the blue sky, but gained a better view of the valley lights. With the prolonged time, stitching did not work. But shooting bracketed shots over a period of time and then using HDR software to stack them up and process them together produced a much better result. And by the way, the evening shot essentially erased any trace of the fisheye effect.
I also did some experimentation with stitching fish eye images together and defishing them also.
The reason why I bring this out, is there are lots of ways to solve a problem with the equipment that you have. You just have to think the problem through. A lot of the solutions do not entail more or new equipment, just using what you have and applying it slightly differently.

Quote:
You mentioned the 10-17 fisheye, but I can imagine this is more a creative/fun lens (even though you can correct the fisheye somewhat in PP) and since it has more or less the same price as the sigma 10-20 f4 that (the sigma) would be, most probably, the optimal pick for me, am I right?
You can do a lot with the fish eye, and yes its a specialty lens. I have found a lot of uses for it.
Actually, one of the above is one of my favorite images that I ever shot. I really wanted the 12-24 to take to sea with me, but there was not enough time to order it and my wife suggested that we wait. So, if I had the 12-24 I absolutely guarantee that I would have had the wrong lens on the camera.
So, am I pushing the fish eye - no, actually I believe that would probably be the last lens that you would get (although it was my first WA thinking that it would be cheaper than the 12-24 and I would get more use from it by defishing). The rectilinear like the 10-20 or 12-24 would be better and easier, and overall probably be more useful.

So here is a thread that I started on my 12-24 decision...
Quote:
I know now why theses lenses are priced the way they are, still it's quite some money for me. Do you believe I should purchase this lens before my holiday in Brasil, I can afford it but I find it still expensive, especially since I have no experience with WA and the more expensive lenses. Or would you think my 18-55 will be sufficient enough?
Knowing what I now know, I would tend to wind up with exactly the same lenses as I now have, but order their acquisition a bit differently. I have been on the "one lens a year plan", saving up and then buying. Now, depending on how your stitching experiment goes, I think that you could well just stitch on your vacation to Brazil and save some money. So what I would do - if I were to do this again, would be....
  • 16-45 - I would start out with this, as a Kit lens replacement. It has better IQ and the difference in focal length you will not miss. If you are short of space in you luggage, then stick to your kit lens, since the 16-45 is substantially larger.
  • 10-20 - If your really want to go wider, then the 10-20 or 12-24 would be my next choice. This is the real WA lens - but its rectilinear so you do not have to worry about the FE distortion.
  • 10-17 - This would by my last acquisition for WA. It is a specialty lens, but with some creativity - you can really extend it beyond just being a fish eye. This really depends on how hooked you become on wide angle lenses.
... and here is a bit of a comparison across some of these.
So, that is another thesis on wide angle lenses. It all comes down to what pleases you.....

interested_observer is offline   Reply With Quote
Old Jul 20, 2010, 5:07 PM   #15
Senior Member
 
Join Date: Mar 2010
Location: Holland
Posts: 105
Default

It seems that you're going to ace that thesis
It's really appreciated.

Stitching is something I've heard about but actually never tried. And this could actually be a nice solution when the craving for these few millimeters wider is high. Haven't thought about that. I will definitely give it a try.

It might be a good idea to begin with a replacement of the 18-55 with the 16-45, this also costs significantly less than start with buying e.g. the 10-20
However, from the reviews I've read that the 16-45 is somewhat sharper and more vivid than the 18-55 it may not be worth the extra money.
Furthermore I do like to travel light.. so I'm still thinking that option through.

I'll dig into the mentioned lenses somewhat more to see what would be the best value for money for me.

Btw I'm probably going to play some poker at the casino here so maybe a win some extra money to buy the 10-20 either way

Take care

JC
__________________
Pentax K-x, DAL 18-55, Tamron 70-300, Sigma 10-20
JC de Jonge is offline   Reply With Quote
Old Jul 25, 2010, 5:51 PM   #16
Senior Member
 
Join Date: Mar 2010
Location: Holland
Posts: 105
Default

Poker went wel, I got home with $450 profit. So I believe I'm going te spend some money on a new lens.
From what I've read the Sigma 10 20 seems to be the best deal. However I've read that there are some unsharp ones amongst them. So I'd best go to the shop and test the lens for a while.
Any suggestions what to look out for while testing? Any other suggestions are also welcome.

Take care
JC de Jonge is offline   Reply With Quote
Old Jul 25, 2010, 8:48 PM   #17
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,056
Default

Don't automatically assume the lens is bad if it appears soft at first - make sure you have some depth in the picture and see if it's back or front focusing, rather than faulty. Also take some pictures of a flat surface, to make sure that the sides are the same, equally distorted. I haven't heard of any of the wide-angles being prone to problems with decentering, but its always worth checking for it. And if you can, take some comparison shots with the kit lens, looking for color and contrast differences, even if they aren't direct comparisons otherwise. If you haven't used an ultra-wide before, make sure you shoot one shot at the widest, making sure you frame detail/subject at the edges. This lets you see what type of distortion you can expect, so you'll know how to use the lens effectively (i.e., don't put people at the edges, unless you want them to look strange).
mtngal is offline   Reply With Quote
Old Jul 25, 2010, 9:33 PM   #18
Senior Member
 
NMRecording's Avatar
 
Join Date: Feb 2010
Location: Eastern Appalachains
Posts: 866
Default

While Ultra wides seem like the best landscaping tools, I actually find them more suitable for architecture and car shows than anything.

Ive taken some very fine landscape shots at 50mm, 135mm, 200mm, even 300mm. Then again where I live sometimes the extra reach is needed to overlook the roads near me to get the beautiful landscape in the background.

My favorite landscaping lens is my 29mm 2.8 and I do have wider lenses.

I'm only making note of this because when I started my search, I was looking for the widest focal length I could, then ended up realizing I was searching up the wrong tree.

For me, every single one of my primes are considered excellent landscaping lenses. This is a great way to go if you don't need auto focus, dont have lots of money, want superb quality and fast aperture throughout your kit. You could get a wide prime for under a hundred dollars. For the 400 bucks you have, you could get 1.8 or 2.8 primes for just about any focal length available and have an excellent kit right off the bat.

Just more to think about, the lens suggestions are superb but IMO the fisheye is going to just make you want to buy another lens. Even if its easy to de-fish it gets bothersome. The fisheye makes a great 5th or 10th lens IMO but not a great 1st or second.

Again just my opinions, interested to see what lens you end up nabbing.

nick
NMRecording is offline   Reply With Quote
Old Jul 26, 2010, 12:45 AM   #19
Senior Member
 
Join Date: Mar 2010
Location: Holland
Posts: 105
Default

Thx mntgal I'll definatly do the checks you proposed.

Nick, indeed I could get a second hand prime in that price range which easily outperforms the lenses I already have, however they are also more heavy and big often. That is an issue for me since I like to travel light and not needing to take a lot of lenses with me.
Also I think for landscaping a super fast lens is not needed per se.
However I do think that a nice (portrait) prime would be my next purchase.

Thanks for your input.

Regards
__________________
Pentax K-x, DAL 18-55, Tamron 70-300, Sigma 10-20
JC de Jonge is offline   Reply With Quote
Old Jul 26, 2010, 7:04 PM   #20
Senior Member
 
NMRecording's Avatar
 
Join Date: Feb 2010
Location: Eastern Appalachains
Posts: 866
Default

no problem, yes the weight is definitely something to consider with primes but not nearly as much as older zooms. I actually prefer the metal build of primes despite the weight and some are a good ratio.

For instance the tokina 50mm 1.8 I shoot makes a nice portrait and is one of the smallest / lightest older primes Ive seen. You barely notice it on your camera.

Dont have a scale to measure it but believe me, its one of the lightest lenses I own

Though you might not need fast aperture for landscapes, it is nice when a lens doubles its number of uses. Large aperture might also be handy for some low light landscapes, IE if the sun is fading instead of shooting on F22 on a slow lens you might be able to go for F11 or F16, each lens has its optimal aperture shooting range and it will allow you to stay within it if your lens shoots on the bright side.

The zoom will benefit you from having to carry several lenses around but while its easier not having to change lenses doesnt mean its going to be lighter.

The sigma 24-60 EX I have is about as heavy as four of my smaller primes.

keep in mind a 50mm on cropped sensor is about 75mm, which I find is a real nice focal length to work with for portraits.

If you want some super light lenses check the Pentax A lenses, (the newer renditions with rubber grips) Ive got a 35-80 and it is super light and nice and sharp. Theyre newer and very light weight lenses.

So Im assuming you're leaning toward that 10-20? Hurry and buy something already so we can see it!! :-D
NMRecording is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 12:39 PM.