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02-20-2012, 08:11 AM   #1
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new to the forum and question on which lens to add for K5

Hello all and nice to be here in this great forum.

I just upgraded from my K10D to the K5 body (amazing improvment for me!), keeping my 10-17 fisheye (which I read is very good) and the (discontinued) 18-250mm DA zoom.
I realize I can do everything with these 2 lens, but having invested in a new great 16mpx body I would like to move from "good" pictures to "great" pictures. I am particularly concerned with sharpens. I like landscapes and outdoor photography mostly, cities, mountains, buldings etc. I see sharpness issues comparing with my friends with Nikkor 18-200.
My question is if it is worthwhile in your opinion to buy a new lens covering a subset of the above range when better quality is needed.
I am evaluating:
Pentax 17-70 (500 euro in Italy)
Tamron 28-75mm F2.8 AF XR Di LD Macro SP (about 350 euro)
Sigma 24-70mm F2.8 IF EX DG HSM (above 600) or 17-70 (maybe)

First of all, would i really see an improvement in Sharpeness with any of these vs my 18-250 or not really? I would go around with one of these most of the time and only if something is really far away switch to the 18-250.

If yes, what would you reccomend? I am going for the Tamron for its costs and great reviews on this site (althought I read everywhere else to be carefull to defective units which are quite common). Not sure the pentax is worthwhile the extra cost and I prefer 75mm rater than 70.

Thanks for yoru suggestions. If 18-250 has same quality I don't buy anything of course.

02-20-2012, 09:49 AM   #2
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QuoteOriginally posted by quintinir Quote
First of all, would i really see an improvement in Sharpeness with any of these vs my 18-250 or not really?
More than likely... Yes you would... Although by all accounts the 18-250 is a fine lens it undoubtedly makes sacrifices that lenses with less range do not... If you were to look at primes (Which I will go on to suggest) these sacrifices are again lessened...

QuoteOriginally posted by quintinir Quote
I realize I can do everything with these 2 lens, but having invested in a new great 16mpx body I would like to move from "good" pictures to "great" pictures.
I dissagree with the first part of your statement... With the 2 lenses you've listed as owning you must struggle with 'lowlight' and to a certain extent 'subject isolation' both of which can be made more possible through the use of faster lenses...
A fast fifty (FA50-1.4 or perhaps the new DA50-1.8) and maybe a 35mm (DA35-2.4) would be good additions to your line-up and definitely improve upon your image quality in the 'normal' and 'short-tele' (portrait) focal lengths...

For your 'Ultra-Wides' for city/landscape perhaps a DA12-24mm-f4 to compliment the DA10-17-fisheye you already own... (?) Although you could use the DA35mm in portrait orientation and 'stitch images' to make truly immense images (due to the apparent 'low-distortion' level of the DA35)...
02-20-2012, 10:50 AM   #3
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Thanks for the suggestions Dave.
About primes, I thought about it, but haven't used fixed focal lenght for last 20 years I am afraid I would be in trouble. Anyway is still an option (my issue is having too many options, also I could give back the used 18-250 for 320 euros (what I paid!), and buy the pentax 17-70 for only 180 and then maybe later purchase a 70-300 later).

About the lens I mentiones above my shop guy just told me (and I would like a confirmation of this) that the tamron 28-75 is a 20 years old projects, designed for film cameras and not really good for K5 (I read here dozens of great reviews so I am confused by his statement. Anybody using it on a K5?). He really suggests the pentax 17-70 f4 also because the price of the sigma would be 750 (!!) which is a lot more.
Now pentax is at 470 and tamron at 440, latest price from my shop. So I could go for the pentax maybe? questions... questions.... sorry about that
02-20-2012, 08:22 PM   #4
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QuoteOriginally posted by quintinir Quote
I realize I can do everything with these 2 lens, but having invested in a new great 16mpx body I would like to move from "good" pictures to "great" pictures. I am particularly concerned with sharpens. I like landscapes and outdoor photography mostly, cities, mountains, buldings etc. I see sharpness issues comparing with my friends with Nikkor 18-200.
Realistically, there is almost zero chance that any differences you are seeing are do to the lens. After all, you're never comparing on the same camera, nor are you probably comparing using the same exposure settongs, or the same photographer. Way too many variables to assume the difference is the lens. If you've got what you think is good set of controlled test shots, feel free to post them, but again, it"s incredibly unlikely you re seeing any difference in lenses here.

Not that there is no point in getting a new lens, but the differences in sharpness between any of these lenses are gojng to be microscopic. No way will ever see the difference in a normal print of image viewed on a computer screen.

02-20-2012, 10:05 PM   #5
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With your 10-17 and 18-250 you are pretty well covered. Look at your best shots and see if you tend to shoot at a certain focal length more that any other and think about a prime, even a limited in that area. It sounds like what you want is a big improvement in image quality and I think you will be disappointed in another zoom. Besides if you pick up say a 15 or 40 or 77 Ltd you can still take along one of your zooms.
02-21-2012, 09:16 AM   #6
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With those two, I'd consider what your "normal" shooting style is and look for a prime in that range. If you're taking close photos maybe consider the 35mm Macro. For snapshots that superzoom probably covers most of what you'd do for casual shooting. For "cool" factor maybe the 40mm Pancake?
02-21-2012, 10:17 AM   #7
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Ok, thanks to all who helped answering. I understand that adding another zoom, althought with narrower bandwidth, would not increase the quality in a such a great way that I would expect spending another 500 euros... So will start looking into primes maybe.

Anyway I still have a little doubt due to the fact that I found in the cabinet a very old pentax F zoom 28-80 from my 22 years old film camera and tried that on the K5... Well, in the corners is evident that is better that the 18-200. I tried the same shots at 28, 35, 50 and 80mm at f4.5, 5.6 and 8 and compared the sharpenes of the two, and the 28-80 sometimes is much better, and (almost) never too worse. So I might hope that a brand new mini zoom in that range should easily beat my 18-250. But maybe 22 years ago the quality was better :-)
02-21-2012, 11:22 AM   #8
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I also have the 18-250 and still use it a lot as it can do so much so well, film era lens also work for me as well. I have gone from the K10 to the K5 and recently purchased the 40mm "pancake". It is the least expensive and perhaps least "eye-popping" of the limiteds but the image quality is dramatically the best in my bag. It is not so much subjective as in your face. So much so that the FA 77 Ltd is next on my list, though I will have to save for some time to manage it LOL

02-21-2012, 12:49 PM   #9
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The 12-24 goes very wide (wider than a prime) if you want straight lines, not like the fisheye. It has excellent IQ and is handy in confined areas like cities.
02-21-2012, 02:48 PM   #10
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some good advices about lens (i found them very useful for beginners, like me)

Worth knowing about interchangeable lenses

The lens is without doubt the most important part of the camera. Choosing the right lens facilitates the uptake of the desired image.

Most SLR cameras (and some rangefinder cameras such as the Voigtlander Bessa series, or the Leica M and of course the new system cameras from Panasonic G-System or Sony Alpha system) have the advantage that changing the lens can be. This can be set depending on the subject, image or design request, a lens with an appropriate angle and / or required luminosity front of the camera.

The viewing angle of a lens is determined by the focal length, whereas the light intensity is given by the maximum aperture (smallest f-number ie). The shorter the focal length, the larger the angle and the smaller the aperture number, the more light the lens more. A lens with a focal length of 28 and an aperture of 2.8 is compared to a lens with a focal length of 105mm and a maximum aperture of 3.5 that is slightly brighter and has a wider viewing angle.
The aperture is measured in so-called f-stops. Each f-stop can be exactly half as much or twice as much light through the lens to the film as the f-stops above or below the set aperture. The stops are: 1,4 - 2 - 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22 - 32 - so that one panel can be half as much so of 2.8 light through the optical system such as a diaphragm of 2 and twice as much light as set fourth panel

Zoom or fixed focal length
Lenses can be roughly divided into fixed focal length and zoom lenses. The advantage of the prime lens is first of all in the more compact design. Moreover, they are compared to zoom lenses of the imaging performance is slightly better. Another advantage is the rather high intensity, which sometimes makes it even without flash or additional lighting to take pictures in low light conditions. This advantage is partially offset by the excellent quality of modern films with high sensitivity (high ISO) almost abolished.

Of 10 lenses are sold at least 9-zoom lenses. They have the advantage over a fixed focus lens, which always has only one focal length and thus a fixed point of view, the advantage that you can change the focal length variable. Thus, changing the angle of view, without having to change the location or "seat" a different lens on the camera. There is therefore the tedious, time-consuming lens changes, the amount of equipment is shrinking and there is no additional high cost of more fixed focal length lenses.

Types of lenses - which lens for what?
The most common types of lenses, the wide-angle, including normal, telephoto and macro lenses. Wide angle lenses have short focal length (24-35mm) and thus a large field of view. Super wide angle with a focal length of 21mm or less have to angle up to 114 . A special place is occupied by the so-called fish-eye lens that is available as a full-frame fisheye or genuine. Both types have at least 180 horizontal viewing angle, the "real" Fisheye also has a vertical viewing angle of 180 , thus you get a circular image sections.

Wide are ideal for landscape, panorama, architecture, advertising, and group shots or shooting in confined spaces. Important in the wide-angle photography, the camera is that it always held horizontally, as this will cause ugly vertical lines. When image formation is to be noted that the focus of design, because the images appear to be otherwise "flat".

The standard lens usually has a focal length of 50mm and is to reflect the perspective of the way she sees the human eye (43mm would be correct!). Due to the wide-angle zoom lenses, where the focal length of 50mm is usually included with, are hardly purchased normal lenses. Only the very high light intensity of 1:1.8 to 1:1.0 irritating photographers who deal extensively with their hobby, or to purchase a normal lens.

Telephoto lenses with long focal lengths from 85mm are ideal for distant objects close to us. The longer the focal length, the smaller the angle of view. It also detects less of a motive, but details can be worked out better. Distant subjects can be to represent a full format. Are ideal telephoto lenses for sports and wildlife shots, but shots can be photographed with them often go unnoticed. Because of the long focal length is shown in the background often unsharp telephoto lenses, so the subject is virtually free. This property makes the portrait photographers advantage. The ideal portrait focal lengths 85-105mm.

Many manufacturers also offer extreme telephoto lenses with telephoto lenses of 400mm or more. These lenses are mainly used for sports and wildlife photographers, and thought, since they are usually built only for professionals, accordingly, expensive.

If you want to completely get close to the subject, then a macro lens is the right one. This is specifically calculated for close range and delivers images to the imaging ratio of 1:1.

Macro lenses are ideal for taking pictures of small animals, flowers and anything less than 5-10 cm. Macro lenses with longer focal lengths have the advantage that the shooting distance is larger for the same magnification. So you can keep the flight distance of living small animals and also has fewer problems with the lighting. Some manufacturers offer even zoom lenses with a magnification ratio of 1:1.8 to 1:2 or even!

Generally, when taking the focal length is equal to the longest possible time in 1/100sek. This means that if you're shooting with a 35mm lens, this is the longest time you can hold in your hand, sec to 1/35. With a 200mm lens with the same light you need is already a 1/200 sec in order to get the shot without blurring! The result is that you need at longer focal lengths corresponding to higher-speed films, so you get to the required shorter shutter speeds. Keep this in mind when buying your movies.
To get even with long telephoto lenses or long periods still images blur-free, Canon and Nikon have lenses with image stabilizer developed. At Canon, these lenses with the addition of "IS" for Image Stabilizer are known, at Nikon have lenses with VR stabilizer is the abbreviation. The optical stabilizer makes it possible to make even at longer times or steady shots without a tripod.

Lens Accessories
The most important accessory for a lens is the lens shade or sun (often mistakenly referred to as the lens hood). The sun visor suppressed unwelcome stray light and thus enhances the contrast of the image. This is especially true for zoom lenses. Most foreign manufacturers ship their lens zoom lenses with the same lens hood. Please use this too, because it was included in the calculation for the optical calculations. Failure to use the solar panel leads to a loss of quality when shooting.

Especially for telephoto lenses, there are converters that multiply the focal length by a factor of 1.4 or 2.0, a 400mm telephoto is 560mm or 800mm telephoto so. Are calculated specifically for a teleconverter lens, it is assumed that hardly any loss of quality is visible. Universally applicable teleconverter always lead to a loss in terms of contrast and brightness, and to avoid a light fall of the center to the edge (so-called vignetting), you should stop down the lens by 1-2 levels.
Almost every lens has a filter thread, for instance spout of a lens or filter to improve or change the way of taking pictures.
02-29-2012, 12:54 PM   #11
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Hi all
Just to tell you the end of the story.... at least so far.
Many people suggested to switch to primes for good quality. I have been suggested 35mm, 40mm (Pancake), 50mm etc. I cannot afford to buy all these lens and with the doubt that was me doing something wrong I selected the cheapest option, i.e the tamron 17-50 which covers all those primes focal lenghts. Before, I read 100 comments about this, the sigma, the pentax 17-70 and even tested the pentax with little improvement honestly (I always used my 18-250 for comparisons).
Bottom line, yesterday I got from amazon the tamron 17-50 and tested against the 18-250. I can assure the sharpness is better (not perfect) at 100% crop, and even better at 50%. I think that at 100% maybe all the pictures looks not perfect? For sure are not perfect with tamron, but better that the 18-250. Maybe a prime would be perfect, I will find out when I have the next 500 euros. The tamron I paid 275 euros only, alternatives were at 500! So I added IQ with little expense. I have to say that I under estimated other parametres looking only at sharpeness. I red about distorsion and color "yellow" but I didn't care. I have to say that the distorsion is really there at 17-20mm, on the side everything is curved and is annoying. And the color is really yellowish. I did only few click so far, so maybe was the bad weather or something... On the other side everybody complains about being "poor plastic". For me looks solid and tough, don't know what they complain about. I did a correction of front focus of -3 on the K5 after testing with a focus test chart. But I don't trust too much this test, maybe I will go back to zero. Anyway, again, there is improvement, but not a WOW effect. I have to compare pictures side by side to see differences at 50%, Mainly I hope to get a more consistent good shot percentage (eliminate the 30% poor pictures, not really improve the 10% perfect). But the pentax 17-70 was exactly the same, only small improvements. Remember I am not an expert, but I did test shooting the same subject with all focal lenghts and apertures to compare. I wonder if a prime like the pancake would have given the WOW effect or would be just another smaill improvement that you can notice only looking at 100% the picture. Canot find a shop where to test it unfortunately.
Again, thaks for the suggestions.
02-29-2012, 01:16 PM   #12
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I guess what I'd say is first, my philosophy has always been slow zooms fast primes... and you have the slow zooms... now you are in perfect position to look at the EXIF information in your photos and determine which length of prime you'd use the most. I have to say we love our 21ltd, but the FA 50 1.7 constantly surprises us. There have been a lot of pictures that jumped out at us when were sorting through our photos that turn out to have been taken with the 50. I just recently figured out how to use Aperture to make folders all taken with the same lens or or camera. It's been somewhat surprising. No use me telling you what I found though, everyone is different. I'd at least go for a Tamron 90 macro or a Pentax 100 macro... just to get top of the line macro shots if you're at all interested in that. Also with the 90 macro, for not that much money comparatively , you can gauge the effect top of the line optics will have on your camera. The Tamron 90 macro was marginally better in IQ to my DA*60-250, I can imagine it would be great compared to your 18-250.

Last edited by normhead; 02-29-2012 at 01:21 PM.
03-01-2012, 01:13 AM   #13
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Hi Normhead,
Macro is a good idea, but now I have to save some money first.
I forgot to say that before choosing the 17-50 vs 28-70 or primes (I use Adobe Bridge) I did search in a folder with about 3000 photos with criteria such as focal lenght between 17 and 50, or between 28 and 70, or above 70 and so on to determine the range most used in the past. Incredibly more than 60% of the pictures where in the 17-50 range, 50% was between 28 and 70 (yes, the tamron is 75, forgot about that) and the rest above 70 and below 17 (I have the fisheye). Only 150 pictures were taken around 40mm so that's why I chosed the 17-50 also vs the pancake 40mm. I don't think I have a way to search and count for macro foto thought, probably they are all taken with 250mm? not sure. Anyway with Bridge (beside that I create folders by camera since ever) you can search by lens, focal lenght, aperture, ISO, time, camera model and so on, so no real need to organize folders because you can filter whenever you want. I also tried to understand if all the best shots with the 18-250 were taken with the same aperture and focal lenght but I had no joy. I think the range around 100mm with f8 looks better, but I found very good shots everywhere and bad shots at 100mm. I wish I knew the trick.... I could not find a deep enough review of the 18-250 where they give you the swet spot so I could use it in the best conditions all the time.
02-25-2013, 01:26 PM   #14
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Thanks for the above discussion, very helpfull
Similar situation here, I'm another new-to-digital guy here (just got a K200D),
starting by using my old Pentax K-X lenses:
Pentax-F Zoom 28-80, the first day -- and I find it's obvious I need a lens hood to fit that, as the above discussion makes very clear. I gather there's no way to close down the aperture when it's mounted on the K200D.

Tomorrow the Pentax-M Macro 1:4 50mm and the Miranda (Pentax mount) 35-70mm macro.
Lots to learn

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