What do these numbers mean?

[m._t.]

Hi, I am new in the photography world, so I'm going to need your help--I have

an Asahi Pentax K1000 SE manual focus film camera and I am looking for a good

macro lens.

 

All of the numbers on the rims of the lenses confuse me and I'm wondering if

these numbers tell me if they will fit my camera. What should I look out for

and what lenses would you recommend?

 

Thank you in advance.

[renatoa]

Can you give an example? Or, let's discuss about this one:

 

http://cgi.ebay.com/SMC-Pentax-Macro-f4-100mm-Lens-Bayonet-Mount_W0QQitemZ190184032160

 

What is unclear to you? 100mm ? f/4 ? SMC ?

[m._t.]

Basically, what I'm wondering is do those numbers indicate a size that can fit on my camera? How do I know the lens will fit my camera? Does every lens fit anything?

 

Does that help you understand?

[m._t.]

Thank you for responding by the way...that's a very nice looking lens!

[jobo1]

http://www.peakoverload.com/blog/photography/a-guide-to-lens-markings/

 

Any K mount prime (i.e., single focal length, non-zoom) macro lens should work OK.

[jobo1]

I use this one, btw, it also exists in a non-AF version that should be even cheaper. The build quality actually is close to the proverbial yoghurt cup...

 

http://www.photozone.de/8Reviews/lenses/cosina_100_35_pentax/index.htm

[renatoa]

Johannes responded, want to add only a hint about the term "K mount". As far as I know you will not find this text engraved on any lens, maybe "PK"

Then, how to recognise a Pentax lens, in a window full with lenses, if the seller is not available?

Simple: look for the "SMC" marking, it designates the best Pentax lenses, it shows without any doubt that lens is a Pentax compatible lens. Also, it should NOT be a DA lens, because DA has no aperture ring, not good for your K1000. This term "DA" is also engraved on the lens body.

I pointed you intentionaly to that lens on eBay, I think it could be good for you and for a budget expected not stelar. The top f/2.8 macro lense are more than $400. The same lens at KEH in an EX+ state is available right now, with warranty, for $225. Expect the eBay bid to finish in the same range.

[mc2imaging]

I don't think that any of the Pentax branded Macro lenses were dogs, but the current

50mm D-FA Macro is one of the sharpest lenses you can find. I have the 100mm Macro

and love it.

<br><br>

Lens markings are not very standardized, so it is hard to be authoritative about what is on

there, but here are some common things you might see:

<br><br>

1:2.8 - This tells you how 'fast' the lens is, or the maximum amount of light it will let

through. In this example, f/2.8 would be the wide open setting on the aperture. A zoom

lens will typically be faster at it's shorter end, so you might see something like 1:4~5.6

<br><br>

55mm - This would typically be the focal length length of the lens. A zoom might show

something like 70~200mm. The bigger (longer) focal length means more magnification.

<br><br>

ø49mm - I doubt that funny symbol in front of the numbers will show up right in a web

browser. It looks like zero with a slash through it. It is a symbol that represents

'diameter' in technical drawings and such. In this example, this lens would use 49mm

filters on the front.

<br><br>

I have seen countless lenses for sale where the seller mistakenly listed information that is

printed on the outside of a filter as lens data. If you see a lens for sale that is described as

a Skylight or UV lens, that is merely a description of a filter on the front end of the lens.

<br><br>

 

SMC - Super Multi Coating. This is a coating that Pentax (and Takumar - another Asahi

brand name) put on the glass of some (but not all) lenses.<br><br>

 

As far as what will mount on your camera, Almost any K-Mount lens will work. DA series

lenses will not, but F-DA lenses will. <a href="http://kmp.BDimitrov.de/"

target"new">Bojidar Dimitrov's Pentax K-Mount Page</a> is a good reference for Pentax

branded equipment, other brands can be a bit harder to know what you are getting....

[stemked]

Let me recommend two excellent lenses manual that are reasonably inexpensive, both avaliable used.

 

Pentax 100mm f4 M macro ($150-200) goes 1:2)

Tamron 90mm f2.5 (0r f2.8) adaptol lens ($125-160). You'll also need to get a K mount adpator for the lens (about $20)

[paul_noble]

The others are correct in that any k-mount lens will fit onto a K1000. They are also correct that the terminology SMC, Takumar or Pentax on the lens means that it is a genuine Pentax lens. AFAIK, Pentax never made lenses to fit anyone else's cameras, so you're safe, with one minor caveat. The last of the Pentax screw-mount lenses were also know as Super-Multi-Coated Takumars. Pentax screw mount lenses CAN be used on a K1000, but it requires an adapter and you lose open-aperture metering and automatic aperture operation.

 

There are a lot of other manufacturers that have made some very fine Pentax k-mount lenses over the years. Vivitar, particularly their Series 1 lenses, are very good.

 

The numbers around the front rim of the camera give quite a bit of information. I'm looking at three genuine Pentax lenses right now.

 

The first is an old screw-mount lens. The lettering around the rim says "Super-Takumar 1:1.4/50 3385656". The Super-Takumar identifies it as a Pentax lens from the sixties, the Spotmatic era, which immediately preceeded the K1000. All Super-Takumar lenses are screw-mount. 1:1.4 indicates that the focal-length to aperture ratio is 1 to 1.4. This is the f-stop, f/1.4. F-stop is the ratio of the focal length of the lens to the diameter of the lens. The 50 indicates it is a 50mm focal length lens. The seven digit number is the serial number.

 

The second says "Pentax SMC-A 1:2 50mm". Again, this is a 50mm lens. The f-stop is f/2.0 (1:2). SMC-A indicates that it is a Super-Multi-Coated lens. This is a proprietary method of coating the lens elements to minimize flare from internal reflections. The -A indicates that it is an A-series lens, which is two generations after your K1000. The A-series lenses were the first to have electrical contacts by which the camera and the lens communicated. Cameras such as the Super-Program and the Program Plus used these contacts to determine the working aperture of the lens. This allowed those cameras to have aperture-priority automatic exposure modes. These lenses will work on the K1000, but are limited to the capabilities of the camera.

 

The third lens is the kit lens from my K10D digital SLR. Its markings are "SMC PENTAX-DA 1:3.5-5.6 18-55mm AL". It also has "52mm" preceeded by a symbol that looks like a zero with a slash through it. This is a greek letter, phi, I believe. You will see this on many lenses. It indicates the diameter of the filter thread. PENTAX-DA indicates that it is a DA, or digital lens. It would fit on a K1000 and would, in fact, produce an image, but the image circle that the lens is designed for will only cover the 16x24mm sensor of the K10D, and not the 24x36mm frame size of the K1000. "1:3.5-5.6" shows that it is a zoom lens and that the maximum aperture varies from 3.5 at the shortest focal length (18mm) to 5.6 at the longest length (55mm).

 

I hope this helps you understand the markings on the lenses you see. There are many variations of this, but in general, you should always see some length indicator, either 50mm, or a range, such as 18-55mm on a zoom lens. Anything that looks like a ratio (1:1.4, 1:2, 1:3.5), is a f-stop.

 

Sometimes the markings are engraved in the retaining ring that holds the front element of the lens in place. Sometimes they are around the outside of the barrel of the lens. I have a Tamron 28-200mm zoom on which the markings are around the base of the zoom ring. On older lenses, the markings were usually around the front element. Today, they can be almost anywhere.

 

Paul Noble

[michael_kuhne]

A good macro lens allows extreme closeups, if that is your goal. Even though you own a manual focus camera now, in the interest of future use, if you can swing it, I would recommend buying a current model, either the Pentax, or the Sigma or Tamron in Pentax mount. Any of those three provide excellent quality. They can be used on film or digital bodies. Although manual focus is often used for extreme closeups, autofocus is helpful for close shots of subjects that move.

[m._t.]

Wow! Thanks to all of you for your amazing feed back! I greatly appreciate it! I'll see if I can pull up some money from the depths and buy a nice K-mount SMC macro lens!

 

Again, Thanks!

M.T.