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Forum: Sold Items 03-25-2013, 06:50 AM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
Price reduced to $350! Free shipping w/in the continental US; actual shipping rate + $10 internationally.
Forum: Sold Items 02-27-2013, 07:49 AM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
Bump!
Forum: Sold Items 02-19-2013, 09:12 PM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
Item is still available at $385 + shipping! Lens is in great shape and is FF-compatible too!
Forum: Sold Items 02-17-2013, 10:47 PM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
PMs sent.
Forum: Sold Items 02-16-2013, 10:31 AM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
PM Sent.
Forum: Sold Items 02-14-2013, 07:50 AM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
Bump!
Forum: Sold Items 02-11-2013, 07:53 PM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
Bump!
Forum: Sold Items 02-09-2013, 05:17 PM  
For Sale - Sold: Sigma 70mm f2.8 EX DG Macro
Posted By kerey
Replies: 11
Views: 2,148
PentaxForums.com Marketplace Listing

Item for Sale
Sigma 70mm f2.8 EX DG Macro

Asking Price
350.00 USD

Item Location
Moscow, ID (United States)

Item Description
Item for sale is a SIGMA 70mm f2.8 EX DG Macro lens in Pentax K mount (covers both APS-C and FF sensors, for future reference :D).

Purchased in LN condition from KEH.com in June 2012 and used very little since then. Objective lens is virtually free of coating defects. The lens barrel exhibits only a single, small scuff to the finish near the serial number faceplate (see photo). Otherwise, finish is clean.

This lens is known for being extremely sharp, and this copy is no exception. A terrific, low-cost option for those just getting into macro work as well as general portraiture.

Sale includes matching threaded metal hood and lens case. I'm willing to ship internationally, with cost/speed to be negotiated based on destination.

PM me with any questions you may have!

Are you the original owner of the item being sold?
No

Are you selling or trading this item?
Selling

Item Condition (Key)
Used
Excellent

Shipping Destinations
Worldwide

Shipping Charge
Free shipping within Continental US; actual rate + $10 Internationally

Shipping Services
USPS, UPS, FedEx

Accepted Payment Types
PayPal

Return Policy & Additional Details
I'm willing to ship internationally, with cost/speed to be negotiated based on destination.

International purchasers will be responsible for any additional fees imposed by PayPal, customs duties, etc. associated with the purchase

Please send me a private message if interested in the item!
Forum: Sold Items 08-20-2012, 06:55 AM  
For Sale - Sold: Pentax-M 50mm f/1.4 with caps and hood
Posted By kerey
Replies: 5
Views: 2,496
Price reduced to $70 plus shipping!
Forum: Sold Items 07-07-2012, 11:16 AM  
For Sale - Sold: Pentax-M 50mm f/1.4 with caps and hood
Posted By kerey
Replies: 5
Views: 2,496
Bump!
Forum: Sold Items 07-02-2012, 06:23 PM  
For Sale - Sold: Pentax-M 50mm f/1.4 with caps and hood
Posted By kerey
Replies: 5
Views: 2,496
Price reduced to $100 plus shipping.
Forum: Sold Items 06-23-2012, 09:05 AM  
For Sale - Sold: Pentax-M 50mm f/1.4 with caps and hood
Posted By kerey
Replies: 5
Views: 2,496
Item still available! Please contact me with any questions you may have.
Forum: Sold Items 06-13-2012, 10:12 PM  
For Sale - Sold: Pentax-M 50mm f/1.4 with caps and hood
Posted By kerey
Replies: 5
Views: 2,496
PentaxForums.com Marketplace Listing

Item for Sale
Pentax-M 50mm f/1.4 with caps and hood

Asking Price
$70

Item Location
Idaho (United States)

Item Description
I've decided to sell my Pentax-M 50mm f/1.4 to help finance a dedicated macro lens. Very minimal use by me; it deserves to be in a more actively-loving home! Condition is 'Good' based upon PentaxForums' Condition Key: some light finish wear on aperture ring, some very small wear points on lens coating (no visible effect on image quality).

Includes lens (serial number 2044637), front and rear caps, and 49mm metal hood (presumably the original, stamped 'Asahi Opt. Co., JAPAN').

Please message me with any questions!







Extent of coating wear:


The circular artifact on the rear element is a reflected CFL bulb, not finish wear :)


Greatest extent of finish wear on aperture ring:


Are you the original owner of the item being sold?
No

Are you selling or trading this item?
Selling

Item Condition (Key)
Used
Good

Shipping Destinations
Worldwide

Shipping Charge
Buyer pays actual shipping (US or international)

Shipping Services
USPS, UPS, FedEx

Accepted Payment Types
PayPal

Return Policy & Additional Details
Sold as-is

Please send me a private message if interested in the item!
Forum: Pentax SLR Lens Discussion 12-16-2007, 01:29 AM  
My Tamron 28-75 2.8 arrived...
Posted By kerey
Replies: 17
Views: 2,885
Hi Tingchaleun-

I had a related experience with an SMC-M manual lens recently, and I was told essentially the same thing. Stop complaining, focus is never 100% accurate, example photos aren't real life, get out and take pictures instead, etc. But there IS a problem, and I can see it in your photos clear as day. Too much front focus. In my case it was a back focus issue, but the basic result is the same: everything looks great in the viewfinder, but the focal plane in the resulting photo is off.

I dealt with it in two ways: more focusing practice (focus improves substantially if I rotate into focus from the left rather than the right) with the manual lens, and I returned my K10D to Pentax (still under warranty) to have the sensor alignment checked. They also adjusted and calibrated the autofocus circuit. Though I don't think the latter did much for focusing with the manual lens, since then I've noticed a slight improvement in focus with my kit 18-55.

If you search around for "back focus" (though you're correct, your lens is front focusing), you'll find many references to this problem. It seems certain lenses cause more problems than others, and some individual camera/lens combos are idiosyncratic also. My guess is that, barring any sensor misalignment or other camera issues (did you notice this problem with other lenses?), a different copy of your 28-75 would work just fine... Good luck!

Kerey
Forum: Pentax DSLR Discussion 11-20-2007, 07:02 PM  
focus with k10d and smc-m lenses?
Posted By kerey
Replies: 9
Views: 2,398
Hi Erik. The K10D is indeed an amazing camera. I recently switched from 4x5 to digital and got myself an SMC-M 50/1.4 to play around with portraiture. I found that though the kit lens seemed to focus quite accurately on AF (and well enough on manual) at ~5.6, the razor-thin DOF on the 50/1.4 highlighted a problem: back-focus. From what I can gather reading posts elsewhere, some cameras (not just the K10D) routinely front- or back-focus when using certain lenses. A few people have been calling on companies to allow user-specified adjustments of the sensor to compensate, but the K10D for one lacks this. If it's minor it can be corrected for during shooting, but if it's major (in my case, REALLY off) then it may be a repair issue. See a recent post of mine (https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/15013-manual-l...t-causing.html).

I suspect few copies of the K10D have this problem, and I'm sure it occurs across companies. It's generated some lengthy discussions elsewhere (link), but I'm not sure the surgery described is applicable to the K10D. Mine was still under warranty, so it's at Pentax now. My best suggestion would be to take your lenses in and test them on a couple copies of the K10D, or be prepared to return one or more for replacements if ordering online. All of this seems strange for me coming from the mechanical, do-it-yourself world of large format, but then again my frames no longer cost $5 a pop either. :D Good luck!

Kerey
Forum: Pentax SLR Lens Discussion 11-17-2007, 11:48 AM  
Manual lens focusing: what is causing this?
Posted By kerey
Replies: 10
Views: 3,198
I appreciate everyone's feedback, and certainly acknowledge this wasn't a real 'test' of anything other than an attempt to show people the problem I was having, using something other than a photo of a tree. The reason for the effort was an entire day's worth of impromptu portraits rendered useless because all were back-focused (though not apparently so on the LCD), so I don't consider my problem to be a minor one or due to unreasonable expectations. To answer Lowell directly, I expect my consumer manual focus lens to focus where I tell it to focus, not (as in the portrait situation) ~1 foot to the rear. This is not an unreasonable expectation, in my opinion, of any product manufactured explicitly for use in the field and in otherwise excellent condition.

I wasn't able to find any reference to this problem prior to my post, but thanks to the link from Fritz I've been able to understand the problem better. As it's still under warranty, I think I'll be sending the camera to Pentax to have the sensor adjusted (rather than attempting the process myself). Hopefully others facing this problem are able to manage something similar.

Kerey
Forum: Pentax SLR Lens Discussion 11-16-2007, 09:37 PM  
Manual lens focusing: what is causing this?
Posted By kerey
Replies: 10
Views: 3,198
OK, deep breath. :p I've been having issues with manual focus on a recently acquired SMC-M 50/1.4, used on a K10D. In short, the point I've been focusing on (based on both visual appearance and the green focus indicator) is consistently blurry, with the resulting plane of focus well behind the subject. I shot the below test targets to make sure I wasn't going nuts. Aperture of f/1.4, OEM focus screen, diopter adjusted correctly, manual focus mode, M exposure mode, shake reduction off, and mounted on a tripod. Oh, and corrected vision (contacts) for my 27 year old eyes. Based on recommendations from others on this forum, I've attached results showing differences in focus based on the direction from which you approach the focus point.

Focused 'from the left', from near to far until green focus indicator lights:
Attachment 5986

Focused 'from the right', from far to near until green focus indicator lights:
Attachment 5987

In both cases, focus looked SPOT ON to the line of text, which actually reads "This text should be perfectly in focus." :hmm: How is this happening??? Some have mentioned the need for a better screen, but these results are WAY off. Are all users of manual focus lenses using a split focus screen etc., or is this an equipment problem? Lens, or camera?

My previous experience with manual focus lenses was in 4x5 with a ground glass, where everything was at it seemed... so this problem really has me stumped. As it is, this lens is unusable at wide apertures, which is of course it's intended use. I can see how there might be a range of focus, resulting in the differences seen based on direction of approach, but NEITHER of them contain the actual point of focus!!! Any ideas what might be causing this?

Kerey
Forum: Pentax SLR Lens Discussion 11-15-2007, 09:07 PM  
SMC-M 50/1.4: focus in viewfinder and focus on frame don't match
Posted By kerey
Replies: 7
Views: 3,329
Well this is sad news indeed, and seems to fly in the face of the enthusiasm for manual focus lenses of some digital users. Is this not an issue for others? I certainly never ran across reference to it while researching the purchase. As a former large format user, the idea that the focus on one's viewing screen doesn't match that in the image reminds me of... P&S cameras. :( I think I may have to sell the lens and save for either the FA50 or maybe that beautiful 50-135.

Kerey
Forum: Pentax SLR Lens Discussion 11-15-2007, 07:48 PM  
SMC-M 50/1.4: focus in viewfinder and focus on frame don't match
Posted By kerey
Replies: 7
Views: 3,329
Thanks for the suggestion re. technique. 'Coming in from the left' helps quite a bit but doesn't resolve the problem completely. The back focus ceases to be an issue around f/8, but that defeats the purpose of having a fast prime.

My question is this: ignoring for a moment the inaccurate focus indicator, How is it that a manual focus lens, optically focused through a clear viewfinder by a user with corrected vision, consistently back focuses? My impression was that SLRs showed ~exactly the view to be captured (not counting % coverage, etc.). I'm doubtful something in the camera is out of alignment, as there's a visible difference between the focus point of the kit lens and the 50/1.4 at f/5.6.

Any ideas on what/who :o could be the culprit?

Kerey
Forum: Pentax SLR Lens Discussion 11-05-2007, 01:26 PM  
SMC-M 50/1.4: focus in viewfinder and focus on frame don't match
Posted By kerey
Replies: 7
Views: 3,329
PS I should mention that although I may be new to manual focus lenses on an SLR, they're not foreign to me. My previous lens was a Rodenstock APO-Sironar N 210mm/5.6 mounted on a Cambo monorail. Where did my ground glass go? Of course, f/1.4 wasn't much of an option in 4x5, but it isn't much use now either if I can't get the plane of focus positioned properly while wielding my K10D.
Forum: Pentax SLR Lens Discussion 11-05-2007, 01:19 PM  
SMC-M 50/1.4: focus in viewfinder and focus on frame don't match
Posted By kerey
Replies: 7
Views: 3,329
I recently acquired an SMC-M 50/1.4, and as I'm new to manual focus lenses, I don't know what to make of a focusing issue I'm having with it on a K10D.

I set the focus to MF, the dial to M, set the aperture on the lens, stop-down using the green button, focus until a) it looks in focus or b) hear the focus indicator beep (virtually always the same thing), then release the shutter. At open apertures, particularly f/1.4-2.8, the resulting frames are consistently focused further away from me than expected. For example, looking down at a fence post and focusing on its very top (as indicated both by the focus indicator AND my contact-lens-corrected vision), with the ground beyond clearly out of focus and an aperture of 2.8, I release the shutter. Reviewing the shot both on the LCD and in Lightroom, I'm getting the ground beyond in focus and the fence top out of focus. But I focused on the fence top!

The same shot with the kit lens doesn't show this, although the DOF from that lens certainly makes the comparison more difficult. The M lens at 5.6 still exhibits a shift in focus towards the background. What's causing this? Poor technique? I'm pretty steady with the camera, and I certainly don't consistently lunge toward the subject as I press the shutter. I don't even know how this might be occurring optically. Any other users noticing this, or do I just need more practice with manual focusing?

Kerey
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