Wide Angle or Fish Eyes?


Rowmac

Link Posted 17/08/2010 - 13:53
Having very recently bought a K-x (very pleased with it), in the mountains of reading and research I've done I've come across wide angles and fish-eye lenses.
My questions are these:
Are wide angle lenses the same thing as a fish eye?
Does a wide angle gradually become a fish eye the shorter the focal length and if so, roughly at what point?
Ideally, I'd like to get a wide angle lense for landscapes et al.
If someone can recommend one (hopefully not too expensive) I'd be very grateful. I don't know if my next question falls into a similar category or not but I'll ask anyway:
I've seen some 50mm fast f1.8, f1.4, f2.8 lenses about as well. Is it to say that you cannot zoom with these lenses? Is it right to think that they have a very big aperture, as such allow lots of light in and thus for fast(er) shutter speeds?

Thanks in advance

Adqam

Link Posted 17/08/2010 - 14:46
>Are wide angle lenses the same thing as a fish eye?
No, they are not. A fish eye lens captures a much larger field of view at the expense of extreme distortion.

>Does a wide angle gradually become a fish eye the shorter the focal length and if so, roughly at what point?
No.

>Ideally, I'd like to get a wide angle lense for landscapes et al.
If someone can recommend one (hopefully not too expensive) I'd be very grateful.

Define expensive! Wide angle lenses are typically not cheap. One of the better lenses for Pentax is the 12-24, which you can find badged as Samsung for around 400.

>I don't know if my next question falls into a similar category or not but I'll ask anyway:
I've seen some 50mm fast f1.8, f1.4, f2.8 lenses about as well. Is it to say that you cannot zoom with these lenses? Is it right to think that they have a very big aperture, as such allow lots of light in and thus for fast(er) shutter speeds?

Yes. Don't forget that a big aperture will also give you a small depth of field.

Helpful

Dangermouse

Link Posted 17/08/2010 - 14:48
The 50mm lenses you've seen are known as primes - they have a fixed focal length so no, you can't zoom with them. The wider aperture allows faster shutter speeds but also allows you to control the depth of field and isolate the subject from the background more effectively.

Wide angle does eventually become fisheye, although I'm not sure at what point. Pentax DSLRs use a sensor which is smaller than a frame of 35mm film, so what would have been a fisheye on film becomes a wide angle on digital due to the crop factor.

As for an inexpensive landscape lens, I like the SMC Pentax and SMC Pentax-M 28mm f3.5. Two different lenses, the former is slightly better but they're both pin sharp and produce excellent results. They are manual and you'll need to learn stop-down metering, but it's worth the effort. 50 should get you a good one if you keep your eyes open and watch the ebay listings.
Matt

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
Last Edited by Dangermouse on 17/08/2010 - 14:50

Rowmac

Link Posted 17/08/2010 - 14:50
Adqam wrote:

>Ideally, I'd like to get a wide angle lense for landscapes et al.
If someone can recommend one (hopefully not too expensive) I'd be very grateful.

Define expensive! Wide angle lenses are typically not cheap. One of the better lenses for Pentax is the 12-24, which you can find badged as Samsung for around 400.

I've got the 18-55 kit lens at the moment. Would dropping down that extra 6mm really make the difference? 400 is a lot of money for me at the moment so I think I shall hold off for a while! Thanks for the help though.
Pentax K-x, 18-55mm & 50-200mm Kit lenses, Pentax FA 50mm F1.4 Prime "DSLR & Photography for Dummies", Gorillapod SLR-Zoom, Hama Profil Duo II Tripod

Dangermouse

Link Posted 17/08/2010 - 15:02
The advantage with the two 28mm lenses I mentioned:

They have very little distortion, so they respond well to an image stitching program. I can create massive panoramic shots by stitching multiple exposures together, producing a wide angle without the distortion of a fisheye lens. Plus, 28mm is very handy as a compact walkabout lens if you get into the habit of always taking your camera with you (as you should - the interesting scenes always turn up when you don't have it to hand!)

Here's an example of such a panorama - taken with SMC Pentax-M 28mm f3.5, at f8, then stitched with the Hugin program for Linux:



Matt

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.

Helpful

Rowmac

Link Posted 17/08/2010 - 16:51
@Dangermouse: I'm sold! Cheers for the help

Edit: This 50mm will work with a K-x, right?
Pentax K-x, 18-55mm & 50-200mm Kit lenses, Pentax FA 50mm F1.4 Prime "DSLR & Photography for Dummies", Gorillapod SLR-Zoom, Hama Profil Duo II Tripod
Last Edited by Rowmac on 17/08/2010 - 16:53

Rowmac

Link Posted 17/08/2010 - 17:48
Rowmac wrote:
@Dangermouse: I'm sold! Cheers for the help

Edit: This 50mm will work with a K-x, right?

28mm, not a 50, sorry. Been doing a lot of research on lenses.
Pentax K-x, 18-55mm & 50-200mm Kit lenses, Pentax FA 50mm F1.4 Prime "DSLR & Photography for Dummies", Gorillapod SLR-Zoom, Hama Profil Duo II Tripod

davex

Link Posted 17/08/2010 - 17:52
Quote:
Would dropping down that extra 6mm really make the difference

You would be surprised.Have a look here

And yes. your KX will work with any K mount lens, to varying degrees of functionality.

Davex.
K5 + 8mm-500mm zooms and primes
Please feel free to play with any images I post.
My flickr: link

Rowmac

Link Posted 17/08/2010 - 18:24
Thanks Davex!
Pentax K-x, 18-55mm & 50-200mm Kit lenses, Pentax FA 50mm F1.4 Prime "DSLR & Photography for Dummies", Gorillapod SLR-Zoom, Hama Profil Duo II Tripod

Dangermouse

Link Posted 17/08/2010 - 22:49
Yes, it would. You will need to set your camera to allow the use of the aperture ring, but that's very simple and will allow you to use other older glass.

Just bear in mind that this particular 28mm is 100% manual. You won't often need to focus it (for most subjects I set it to infinity at f8, this works well with car-sized objects as by the time you're far enough away to get it all in the frame it's in focus at infinity) and the focus confirmation beep/hexagon in the viewfinder will still work. You will need to use stop-down metering, but that isn't complicated.

IMO it's a lot sharper than the 28mm f2.8 which Pentax carried forward into their A series of lenses (which have the contacts to allow you to use all the exposure modes on a DSLR) and it's also a fair bit cheaper.

Here is one of the lenses in question - I think that one is overpriced, I paid about 50 for mine which was much more sensible.
Matt

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.

bychan

Link Posted 18/08/2010 - 00:19
Rowmac wrote:
Having very recently bought a K-x (very pleased with it), in the mountains of reading and research I've done I've come across wide angles and fish-eye lenses.
My questions are these:
Are wide angle lenses the same thing as a fish eye?
Does a wide angle gradually become a fish eye the shorter the focal length and if so, roughly at what point?
Ideally, I'd like to get a wide angle lense for landscapes et al.
If someone can recommend one (hopefully not too expensive) I'd be very grateful. I don't know if my next question falls into a similar category or not but I'll ask anyway:
I've seen some 50mm fast f1.8, f1.4, f2.8 lenses about as well. Is it to say that you cannot zoom with these lenses? Is it right to think that they have a very big aperture, as such allow lots of light in and thus for fast(er) shutter speeds?

Thanks in advance

Whilst I've never used a fisheye, I do own a Sigma 10-20 which is classed/regarded as an ultra wide angle.

What I really like about it is not the fact that you can try and cram more details into the shot, but the totally different perspectives and angles it provides. It's also surprising how close you can get to your subjects.

Some examples of the 10-20 & Kx in action.
link
link

Regards
Adrian
K5IIs, Sigma 10-20, Pentax DA 16-85, Pentax DA 55-300, Pentax 70 Ltd, Metz 44 AF-2.
Flickr: http://www.flickr.com/photos/ambott/

Smeggypants

Link Posted 18/08/2010 - 05:21
I've recently bought a Pentax DA 10-17mm Fish Eye Zoom.

No regrets whatsoever. The image quality is superb and the distortions are easily corrected in Lightroom 3 or PTLens should you require it. I rarely do as the distortion add to the fun.

If you want to capture the glory of open landscapes this lens is superb!!
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283

Banjo

Link Posted 18/08/2010 - 08:28
Rowmac wrote:
...Ideally, I'd like to get a wide angle lense for landscapes et al...

Many photographers long for wide angle lenses so they can take landscape images.

I too have fallen for this.

However, having had the experience, I'd like to sound a warning.

Wider lense do get more of the countryside into the picture, but all the objects in it are much smaller. Not only that, they are all pushed to the back of the picture resulting in an enormous -often wastefully empty- foreground. Wide lenses have the effect of making quite impressive features (hill, trees, buildings etc) look absolutely insignificant in the print/slide.

Not only that, but any object -e.g., tree branches or the arm of your subject- lying axially (along the line of sight) becomes elongated out of all proportion, looking bizzarre.

Also, the effect of any tilting of the film-plane (camera up of down) results in vertical objects (trees, people) leaning strangely into or out of the picture. Circular objects become strangely oval.

Very wide angle lenses (20mm or less) are relatively quite expensive and quite tricky to use well: you may neede to revamp all you thought you knew about "composition" to obtain acceptable results.
Last Edited by Banjo on 18/08/2010 - 08:28

Rowmac

Link Posted 18/08/2010 - 10:27
As much fun as a fisheye/very wide angle lens would be, from reading comments about their versatility and the various issues to get them to produce good results; Costwise, I think might be better off sticking with my 18-55 and consider a 28mm f2.8 or wider 50'ish lens that Dangermouse talked about a little earlier in this thread. A compromise, I know, but I don't have the moola to fork out for a 400 ultra wide angle >.
Pentax K-x, 18-55mm & 50-200mm Kit lenses, Pentax FA 50mm F1.4 Prime "DSLR & Photography for Dummies", Gorillapod SLR-Zoom, Hama Profil Duo II Tripod

Dangermouse

Link Posted 18/08/2010 - 11:40
What I will say is that where manual focus Pentax lenses are concerned the f3.5 versions of the 28mm are superior to the f2.8 versions. You don't need a particularly fast lens for landscapes and the images are much sharper. Took this a few days ago with my recently acquired K 28mm f3.5 at f3.5 and infinity:



Matt

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
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