Hi, I'm fairly new to the world of photography and need some help understanding what different size lenses do? More specifically what does 1:2.8 as opposed to 1:2 mean? I have tried to ask this question in a few retail camera shops and found myself surrounded by arrogant sneers. Fairly hostile environment for a beginner and lover of photography. Also, I have a 100mm lens 1:2.8, for my Pentax K1000 that i'm getting fairly tired of. I'd like to try a wide angle lens and a macro, any suggestions? I like B&W primarily. thanks for all your help Nancy

-- Nancy (cardle2@home.com), September 10, 2001

Answers

The Pentax 50mm lens in the K mount is super sharp, could be purchased for very little and would probably be fairly easy to find. I would stick with a Pentax SMC rather than another brand.

The number following "1:" refers to the lens' largest aperture. For example, the largest aperture of your 100mm is f/2.8. If you are still confused, it might be best to browse through a book on a basic photograhpy.

-- Joe Miller (jmmiller@poka.com), September 10, 2001.

Congratulations, you have one of the best cameras available to learn photographic techniques. You may go on to automated equipment later, but you'll have knowledge that will always be useful.

Apertures are measured in f-stops, which (from widest to smallest) go 2.0, 2.8, 4, 5.6, 8, 11, 16.

(The retail clerks' sneers, by the way, probably mean they have no idea how to answer your question, They typically know as much as they read on the back of the camera box, and that's the limit. The reason they can't answer a question about f/2.0 apertures is that the point and shoot cameras they sell simply do not have apertures that large. Neither do the zoom lenses for SLR's.)

The K-1000 goes very well with a 50mm Pentax SMC (Super-multi-coated) lens with an f/2.0 maximum aperture. These lenses are inexpensive (used) and pretty good performers. The 2.0 aperture is good enough for low light (non-flash) photography. The 50mm focal length is what some used to call a "normal" lens -- which means it approximates what you see with your eyes. The normal lens is a great one to sticvk to when you are learning photography, It enforces the discipline of evaluating what you see in the viewfinder, and actually moving around to compose your shot, instead of settling for a zoom lens adjustment.

The f2.8 100mm is actually a pretty useful lens. I use a 135mm (which is a nearly extinct focal length, but just got some good press in a photo magazine). Your 100mm will be good for street shooting and portraits.

For a wide angle lens, you are probably best off with a 28mm f/2.8. There are plenty of used ones on the market. Stick with Pentax or Takumar (an early Pentax lens name).

For macro pictures, get a set of diopter adapters that screw on the front of your lens. (The nice thing about my Pentax lenses is that they are almost all 49mm filter size, so I can use filters on any lens.) Everyone will tell you that these close-up lenses produce lesser quality images. They are right. But, the price is right, you can use them on your 50mm or 100mm lenses, and when you get good at macro photography, you can spend the money for a proper macro lens.

Finally, I suggest that you get to the library and start reading.

(I practice what I preach. I have a Pentax KX variation of the K-1000, and Pentax fixed focal length lenses in 28mm, 50mm, 85mm, and 135mm. I almost always shoot handheld. I shoot B&W exclusively with Tri-X film.)

-- Jeff Polaski (polaski@acm.org), September 10, 2001.

Nancy,

The numbers (1:2.8; 1:2) indicate the aperture size, or f- stop. "Aperture" is the opening in the lens, and determines how much light gets through to the film.

The bigger the second number (2.8 or 2) the SMALLER the opening, the less light comes through. Smaller numbers give bigger openings, and more light.

This is the reverse of what might seem logical, but it is because these numbers (called f-stops) are fractions, so a bigger denominator means a smaller size (1/2, or one-half, is bigger than 1/8, or one- eighth). The reason for the "/" or ":" in the number is to indicate fractions or ratios.

The "traditional" group of 3 lenses for a 35mm camera are 35mm, 50mm, and 90 mm. These are slightly wide angle, normal, and slightly telephoto respectively, and a fine place to start. Some people prefer stronger effects in the wide & telephoto, and choose 28mm & 135mm lenses for these.

For macro work, you might consider getting a 90mm macro lens for close-ups, and good ones can also be used for normal work with good results.

Hope this helps.

-- Charlie Strack (charlie_strack@sti.com), September 12, 2001.

Nancy:

Ignore the fools in the camera stores. They probably don't know how to answer your question, or they would. Also they'd rather sell you something new and expensive.

Pentax has made excellent cameras, including the K-1000, for many years. Older manual-focus lenses are often extremely inexpensive used. Try keh.com for a vast supply; they're a very reputable dealer in Atlanta and you can order on-line or over the phone.

Depending on how much you want to spend, I'd suggest looking for a 50mm f/1.4 or f/2 lens. 50mm lenses -- the old "normal" length for 35mm cameras -- are brilliantly sharp, well built and cheap, in some degree because they're out of fashion at the moment. You can get a 50mm/2.0 at keh.com for $40; the f/1.4 is $120. The difference is one stop of light -- the more expensive lens can take a picture in slightly darker circumstances, all else being equal.

Get the SMC-M version for a K-1000; other more expensive versions (like A, F and FA) will work, but you won't be able to use their extra features on your camera.

Next recommendation is a 28mm f/2.8 -- a nice little lens twice as wide as a 50 and four times as wide as your 100. You can get one in bargain condition for $70, excellent condition for $100.

A wonderful little cheap Pentax lens is the 135mm f/3.5. Dead sharp, well built, even has a built-in lens hood. A little longer and a little faster than your 100. Bargain condition, $50.

All these lenses use the same size filters -- 49mm -- so one set of filters will do for all your glass, including your 100/2.8.

For macro work, you might look at a 100 f/4 macro, though it's a bit more money than some of these other lenses, more like $250 to $300, depending on condition.

Finally, for lots more information on Pentax equipment, check out www.pdml.net. It's a pretty international group of Pentax lovers who also know a good deal about photography, though at the moment they're a little absorbed in the WTC bombing.

Have fun,

Bob Keefer

-- Bob Keefer (bob@bkpix.com), September 13, 2001.

I have been using Pentax 35 mm cameras for over a decade: first the P3n and now the MZ-5. I strongly recommend all of the A series lenses. My favorite is the 35mm f/2.8. It is great for street photography and moderate wide landscape. My 50mm f/1.7 is the second most used lens in my bag. I also have the 100mm f/4.0 macro and the 150mm f/3.5. I think the 150 is an M series lens. I'm not sure. I'm at work and my camera is not. Also, these lenses can be used on the modern cameras if you eventually want to take advantage of multisegment metering, auto advance, auto bracketing or other modern features (excluding auto focus).

-- Edward Kimball (edward.kimball@ns.sympatico.ca), September 13, 2001.

I always find time to broose local pawn shops. I know to some this might seem strange but I have found Pentex K-1000's at great deals with original lenses and some also have the original case and booklet. These are great cameras for many reasons but they are a wonderful way to teach kids the basics of taking pictures! Get as many as you can! Peace, Linda

Get as many as you can!

peace, Linda

-- Linda (shakti265@aol.com), September 23, 2001.