[Lodderup]

Yello guys.. !

Let me first of all say: "hi, glad to be a part of this forum"..
I'm a 22-year old guy from Denmark, with a passion for photography. In most eyes probably a very immature young guy, when spending 4/5 of the monthly payment on a camera and a dream.. But then again, why spend your money on food, when all you need is love?

A few months ago i bought my first DSLR, the "mighty" Pentax K-x, which i am more than thankful for.
Since i received "her", i have spent loads of time taking pictures from nightlife scenes and general nature (i admire the vivid colors of blue skies and seasonal forests).

All this was enough for me, until now. I now want to get deeper into the theoretical side of photography, but i must admit, there are a lot of difficult terms and quite meaningless phrases.

So please answer me this:

• What is a 35mm lense/body? And is it compatible with regular SLR's?
• Which new lens would you guys recommend, when the criterias are: "Budget of max. 120$" & "Must have at least 200mm zoom"
• What is the difference between DA and DA* lenses?
• What defines a "Telephoto" lens?
• ... And what is all this fuzz about Screwmounts, M-42 mounts and "adapttoall"?

Well-knowing that a 200mm lens is not of the highest quality inside this price range, i would like to practice handling a fast auto-focusing lens, until i finally win the lottery.
Oh yeah.. and those compatible "lens solutions" sound like weapons from WW2..?
Is there a connection?

[Peter Zack]

First, welcome to the forums. Great place to hang out.

To your first question, 35mm refers to the image 'pickup' size. That first meant film sizes that are 24x36mm (actually 24.3 x 35.8mm). On a Digital SLR, APSc is a smaller size and varies between manufacturs to some degree. There's no standard and Pentax is 1.54 crop factor. This means that the sensor is 23.6 x 15.7 (370.52 mm2) vs a 35mm film or FF digital (869.94mm2).

So what does this mean to you? Well a 200mm lens acts like a 300mm lens in terms of Field of View (FOV). It doesn't actually magnify more, but the image is cropped by the 1.54 factor and thus acts like a longer lens than it is. Overall APSc sensors are very similar to 35mm (often refered to as Full Frame (FF)) but the FOV and the Depth of Field (DOF) are different. A 50mm lens is wider in it's FOV and has a shallower DOF on FF vs APSc. The other thing is a typical (there's a ton of debate on this) FF sensor has a lower pixel density than an APSc sensor and many (including me) believe that pixel density has a lot to do with digital noise.

Consider that a 14.5MP chip as in the new K-7 is equivalent to a 21.75MP sensor on a FF camera. Now look at a camera like the Nikon D700 as a FF and 12MP. The K-7 has considerably higher resolution and many believe that causes sensor noise at higher ISO's (sensitivity) The plus with APSc and the higher resolution is, at lower ISO's, you can crop the final image more and still retain enough data to print to a large size.

To your second question. $120 for 200mm is possible but you are limited at this price. Your 2 best choices IMO are the Pentax F 70-210 f4-5.6 auto focus lens. A very sharp lens that is older and only available on the used market. A bit noisy but should be given serious consideration. The other would be the even older Takumar M42 screwmount lens. Also a very good performer but totally manual.

DA vs DA* lenses. The DA's are the regular "consumer" lenses. More budget priced and typically "slower" lenses and often variable aperture. The quality is solid though optically. "Slower" refers to the max aperture on the lens. An f2.8 lens is 1 stop faster than an f4. This means that more light can pass through the lens and it (in theory) should be better in low light and faster focusing.

DA* lenses are the Top tier models. Superior optically in a number of factors. Less barrel distortion (curved lines at wide angles), sharper even at wide open. Also renders a better image in a number of factors.

Telephoto is typically 100mm or more. This is debatable and I don't think there's a set definition. But most would consider (APSc) that 50mm to 77mm is portrait length. Telephoto is around 100mm and longer. Normal focal lengths (roughly what your eyes see) would be 25-40mm and wide is below 25mm (really below 20mm).

"Fuzz"???? Did you mean Fuss? Adaptall and M42 screwmounts will work on Pentax bodies. Pentax partly maintained their mount that has been in use for about 30 years or so. Before that, they used the 42mm standard screwmount lenses and a simple adapter can be used to fit these lenses to the body of a modern DSLR. Adaptal lenses have a universal mount on the lens itself and you buy the adaptal mount you need for your particular brand. So for Pentax there is a P-K adaptal (no aperture or electronic connections) and a P-KA version that should transmit exposure data to the camera from the lens and this can depend on the lens attached. IMO it's a nice idea that doesn't work well. It should have taken the market by storm but didn't last and Tamron abandoned the system. The idea was that a single lens could fit any brand of camera and work normally. For the most part they do. I found that the exposure data was never accurate and of course auto focus was impossible since each manufacturer used different systems. When AF came in, this idea died.

M42 is a fun idea for cheap and good quality glass. IMO everyone should give it a try and see if they like it. For me it was a mixed bag. Many if not all Takumars are some of the best lenses you may ever use. But the DSLR mount is crippled. It can't communicate with the lens at all. As far as the camera knows, there's no lens attached. There is the Green button that is supposed to give a meter reading at whatever aperture the lens is set at, but that system is poorly implemented. It is wildly inconsistent and IMO was designed to make people feel that they could use the old lenses in some normal fashion when actually is a guess most of the time. Exposures can be -2 to +2 stops at any given aperture. Far too variable to be trustworthy. But if you can estimate in your head or have the time to bracket an exposure (several shots of the same scene at different exposure settings), then these can be fun and enjoyable lenses. Plus if you use a particular lens a lot, you'll get used to how it works on the body and get decent results. Even though I personally was very disappointed in the crippled mount, some of my best shots were taken with Takumars.

You will not get a "fast" Auto Focus lens at $120.00. In fact we may be confusing the terms. When most of us refer to fast, we mean the maximum aperture opening. Slow is F4 and above. Moderate would be f2.8 (but as fast as any zoom is) and "fast" would be f2 and more. A lens like an f1.4 is very fast and f1.2 is about as fast as you can find.

You may be meaning 'fast' as in 'fast to focus'. The lens I mentioned above is quite good in that respect. Some are good and other suck. One that fits this catagory is the DA* 16-50mm f2.8 lens. Nice optically but a lens that should be avoided and IMO needs to be dropped from the line. A disaster from the begining. Now that I have a Tamron 17-50mm f2.8, I see how terrible this DA* lens really is.

I don't get the WW2 reference.

[Stringmike]

The recommendation on lenses depends on what you are looking for. If you are wanting something small and light with auto-focus, then the more modern lenses designed specifically for cropped-sensor digital cameras might be a better bet. They are generally quite a bit smaller and lighter than their old counterparts designed for 35mm full-frame cameras. I have a selection from Tamron and Sigma that work well and are much less expensive than Pentax brand equivalents.

I grew up with older Pentax film cameras and have a selection of older manual-focus lenses that I still use. In the 200mm range, I use a very old Tamron Adaptall 70-210 f3.5. I bought this for $99, new in the box, old stock. The Pentax KA adapter (that enables this lens to mount on a Pentax camera and still control the aperture) cost another $75.

The old Pentax primes are legendary - I have a number of 50mm manual focus, as well as a 28mm - many of these are under or around $100. My favorite old zoom lens is the Pentax 35-105mm f3.5 ($120 to $175) - it covers a useful range, is very sharp and has great color.

Check out the lens review section of this forum - you'll see a lot of good information from actual Pentax users.

Good luck, and enjoy your new camera:

Mike

[Phil1]

A good referance:
http://www.robertstech.com/compat.htm

[bdery]

You got some great answers so far. I'll reply to the telephoto under 120$ question.

I recommend two options:

1-Vivitar series 1 70-210, versions 1 or 3. These are amazing lenses, on par with many modern pro lenses, and quite inexpensive. The version 3 is optically the best, version 1 is a good pseudo-macro, and both are relatively cheap.

2-Pentax FA 100-300 mm f4,7 (NOT f4,5). This plastic, underrated lens, is a favourite of anyone who has used it. Less aberrations than the vivitars but also less sharpness, it can be had for about 100$.

[elpolodiablo]

Hmm, about the $120 200mm zoom,

I am surprised no one mentioned Pentax DA/DAL 50-200, there are 3 version (including the WR version)of this lens but optically they are all the same.

I used to own DA L and DA WR version of this lens, and no, it's performance is not as good as the DA 55-300 I currently own but given sufficient light it still performs pretty good, and you can have one used within your budget easily except the WR version, check the market place here.

But again I don't own any of the lens some has recommended so maybe they know something I dont.

Oh and enjoy your K-x, I know I am loving mine

[Lodderup]

1)
First of all, thanks for all the input. It is a jungle of different references and terms, so just when mentioning "APC" i constantly confuse it with an armored personal carrier.
So if i get it right, a 35mm lens, is a lens that crop the picture to a far more widening resolution, than a standard camera? (Like a movie perspective?)

2)
About the Tamron 70-210, i read the same recommendation around the net. But then it comes to an even further detail: What is "LD" and "Di" ... And is it worth it to pay 50-75$ more for the "Di" addition?
And is the old "FA 100-300" lenses (f.x. Sigma or Pentax) still worth a shot?

3)

The old Pentax primes are legendary - I have a number of 50mm manual focus, as well as a 28mm - many of these are under or around $100. My favorite old zoom lens is the Pentax 35-105mm f3.5 ($120 to $175) - it covers a useful range, is very sharp and has great color.


Mike

There's another reference i need explained: "Prime" lenses. Is it "prime" in the interpretation that it is old/legendary? Or because its standards/build up is equal to the old lenses?

[Transit]

There's another reference i need explained: "Prime" lenses. Is it "prime" in the interpretation that it is old/legendary? Or because its standards/build up is equal to the old lenses?

Photography certainly has its share of confusing terms
Prime means a fixed focal length lens. ie: 50mm.
The other kind is zoom lenses that change the focal length
like that vivitar.

I googled 'what does Di mean Tamron' and got this

Pete

[Rondec]

1)
First of all, thanks for all the input. It is a jungle of different references and terms, so just when mentioning "APC" i constantly confuse it with an armored personal carrier.
So if i get it right, a 35mm lens, is a lens that crop the picture to a far more widening resolution, than a standard camera? (Like a movie perspective?)

2)
About the Tamron 70-210, i read the same recommendation around the net. But then it comes to an even further detail: What is "LD" and "Di" ... And is it worth it to pay 50-75$ more for the "Di" addition?
And is the old "FA 100-300" lenses (f.x. Sigma or Pentax) still worth a shot?

3)


There's another reference i need explained: "Prime" lenses. Is it "prime" in the interpretation that it is old/legendary? Or because its standards/build up is equal to the old lenses?

A prime lens is a lens with a fixed focal length, for instance, a 43mm prime lens is only that. This is as opposed to zoom lenses, where there is a range, for instance 18-55mm. Primes tend to be smaller, a little faster and have better sharpness edge to edge.

As for the APS-C crop factor, I wouldn't worry about it too much. It is most useful for people who used to shoot film and know how their lenses behaved on film. Basically, an APS-C sensor is smaller than a film negative is. This means that part of the image circle seen by the lens is just thrown away, since the sensor doesn't cover it. To make a long story short, this means that your field of view ends up being more narrow on APS-C for the same focal length as compared to a "full frame" sensored camera. It is probably more useful over all to know what your field of view is with your current lenses and current camera and not focus on the crop factor. Good luck!