[Barron]

info from the pros!

First off I am new here and hope to not spend too much time, but that probably won't happen.....I'm also not very educated in the area of photography, but I'm slowly learning.
I currently own a K10D which I bought in order to get some decent photos of my 2 year old son and also for taking pictures of the guitars that I build for my business. I wasn't aware until just recently that I could use basically all of the older Pentax mount lenses with my K10D. very cool indeed! Especially since it's hard for me to spend the money on the newer lenses.
So I found someone local who had an enormous amount of older lenses and bought a bunch of Pentax mount lenses off of him. I'm hoping to keep a couple that will suit my needs and sell off the rest.

Among them I found 2 that I can't dig up much info on and would appreciate anything you may know about them.

1.) Rexetar Auto Zoom Supercoated J/525 1:4.5 f=80-200mm

2.) JCPenny Diamatic 1:3.5 f=200mm (screw mount)

The others I bought are:
takumar 1:3.5-4.5 28-80mm
takumar-f zoom 1:3.5-4.5 28-80mm
takumar bayonet 1:2.8 135mm
pentax smc f zoom 1:4-5.6 70-210
smc pentax-m 1:2 50mm asahi (x2)
smc pentax-a 1:2 50mm
smc pentax-a 1.7 50mm (x2)
super takumar 1:1.4 50mm (with double converter)
tokina sd 70-210mm 1:4-5.6
auto vivitar tele zoom 85-205mm 1:3.8
2.8 takumar 135mm
Vivitar 28mm 1:2.5 Auto Wide-Angle

[Ash]

Welcome to the forum Barron.
Hope you enjoy it.
You seem to have amassed a large collection of manual focus lenses.
If there isn't an M42 to K-mount adapter amongest any of your screwmount lenses, you will have to purchase one to be able to use these lenses on your K10D.
Otherwise, you should be good to go with all of them (if they're all K-mounts).

The A lenses you've listed are the easiest to use, just mount, focus and shoot. The best of them is the A 50 f/1.7 (if you don't need two, you can give one to me ). These lenses can have their apertures controlled by the camera, so totally automated except for the focusing.

The M lenses, M42 lenses (screwmount) and their equivalents do not have the electrical contacts required for controlling the aperture via the camera, so you will need to do this manually on the lens itself. The M lenses will require an extra step in being able to stop them down (use a smaller aperture) called 'stop down metering'. This is achieved with the green button - you can see how to do this from your manual or look at the article outlining this procedure in this forum. The M42 lenses do not need this step as they are completely controlled by their aperture rings, and if you stop them down they do so even before the shot is taken as opposed to M lenses that remain wide open until the shot is taken (to stay bright while you look through the viewfinder).

Hope this helps.

[Barron]

Welcome to the forum Barron.
Hope you enjoy it.
You seem to have amassed a large collection of manual focus lenses.
If there isn't an M42 to K-mount adapter amongest any of your screwmount lenses, you will have to purchase one to be able to use these lenses on your K10D.
Otherwise, you should be good to go with all of them (if they're all K-mounts).

The A lenses you've listed are the easiest to use, just mount, focus and shoot. The best of them is the A 50 f/1.7 (if you don't need two, you can give one to me ). These lenses can have their apertures controlled by the camera, so totally automated except for the focusing.

The M lenses, M42 lenses (screwmount) and their equivalents do not have the electrical contacts required for controlling the aperture via the camera, so you will need to do this manually on the lens itself. The M lenses will require an extra step in being able to stop them down (use a smaller aperture) called 'stop down metering'. This is achieved with the green button - you can see how to do this from your manual or look at the article outlining this procedure in this forum. The M42 lenses do not need this step as they are completely controlled by their aperture rings, and if you stop them down they do so even before the shot is taken as opposed to M lenses that remain wide open until the shot is taken (to stay bright while you look through the viewfinder).

Hope this helps.

Hey - thanks a lot! I do have the adapter and have tried out all of the lenses just earlier today. And I was absolutely twisting a bunch of rings today like you said I would..
I'm really digging the 1.7 and the 1.4. I'm not sure which I like better at this point. I would probably need to shoot in some different lighting situations before deciding.

Here's one that I took with the 1.4 today of some camera bodies that I was forced to take when I bought the lenses..(sorta low light situation)



Uploaded with ImageShack.us






Here's one I took at night with the 1.7


Uploaded with ImageShack.us

[RioRico]

Hi Barron, and welcome aboard. That is indeed an interesting pile of lenses you bought! I'll comment on some of them. For in-depth information on the Pentax-Asahi-Takumar lenses, see the review database here. And of course, the acid test for any lens is, DO YOU LIKE WHAT IT DOES? If you do, then other folks' opinions are irrelevant.

> 1.) Rexetar Auto Zoom Supercoated J/525 1:4.5 f=80-200mm

Too many old manual zooms, especially the no-names, just don't approach the quality of newer zooms. And many lensmakers churned out lenses that marketers named; tracking down the maker may be difficult. Rexatar is one such no-name brand, quite variable in quality; that's why I sold my two Rex primes, a 135/2.8 and 200/3.5. You *might* find this Rex zoom usable in good light -- try it and see.

> 2.) JCPenny Diamatic 1:3.5 f=200mm (screw mount)

I've seen 'Diamatic' on the no-name Accura brand, but a JCPenny Diamatic is new to me. JCPenny, Sears, K-Mart (Focal brand), and other stores bought various lenses from many makers, often from the same makers as Vivitar. These store-branded primes are often quite good. Again, try this one out.

I have a simple lens test: Aim it at a bright light that has straight edges nearby (shelves, standards, etc). Shoot, then chimp (review) the picture, zooming in. If I see wide colored fringes at those edges, I sell the lens. Narrow fringes are OK for me.

> takumar 1:3.5-4.5 28-80mm
> takumar-f zoom 1:3.5-4.5 28-80mm
> pentax smc f zoom 1:4-5.6 70-210

I can't really comment on these. See the lens review database. I will say that if those are SMC-F zooms, they are worth keeping -- or sell them for a good price!

> takumar bayonet 1:2.8 135mm
> 2.8 takumar 135mm

The Tak bayonet gets little respect, but it's still a pretty good lens when used right. Are you sure the other Tak 135 is f/2.8 and not f/2.5 or f/3.5? No Tak 135/2.8 shows up in the lens review database. All the screwmount Tak 135's are damn fine lenses, highly regarded.

> smc pentax-m 1:2 50mm asahi (x2)
> smc pentax-a 1:2 50mm

These are both very common, and also get little respect, because they're outclassed by the faster 50's. I have 3 M50/2's that just aren't worth selling yet. The A50/2 is in greater demand simply because A-type lenses are easier to use. But an A50/1.7 will SMOKE it!

> smc pentax-a 1.7 50mm (x2)
> super takumar 1:1.4 50mm (with double converter)
> Vivitar 28mm 1:2.5 Auto Wide-Angle

These are all SUPERLATIVE primes -- never let them go! Well, hang on to your extra A50/1.7 for a few months, and sell it for a high price. What brand is the 2X TC (leleconverter)? Try it and judge its results. Most 2X TC's give worse image quality than just cropping and enlarging the picture.

> tokina sd 70-210mm 1:4-5.6
> auto vivitar tele zoom 85-205mm 1:3.8

I can't really comment on these, except to say that zooms with a fixed maximum aperture (like the Rex f/4.5 and the Viv f/3.8) generally have better optics than zooms with floating max apertures (like the Tokina f/4-5.6). That is a generality; exceptions abound. Again, try them and see for yourself.
______________________________________

I've been in the lens trade on eBay for awhile, buying and selling glass so I can buy and sell yet MORE glass! Prices for old Asahi-Pentax lenses have spiked and show no signs of dropping. Even no-name Pentax-mount lenses have jumped in price. Whatever you decide to sell, you are not likely to lose money, as long as the lens is well-described. Have fun!

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Last edited by RioRico; 06-06-2011 at 08:53 PM.

[Barron]

Rio - first let me say thank you for taking all that time to write up what you did.
Sorry - the Tak 135 was a mistake as I was distracted at the time.
I will take a longer look at the fixed max aperture and also do the test you referred to earlier.