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01-12-2010, 06:33 AM   #16
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You could try selling the Sigma and buying a Tamron, you will no tlose any money (may make a little). The Tamron should be a tad sharper. The 55-300 is around $300 used on this forum, sell your siggy for maybe $125, you still need $175.

'tis tricky.

01-12-2010, 06:42 AM   #17
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If you keep your eyes open, you can find the DAL version of the Pentax 55-300 on ebay for about 250. That is probably the best you can do, but IMHO it is a significant step above the other options out there. I owned the Sigma 70-300 and it was pretty weak. Muddy colors, slow focusing, but it got me by till I could afford other options.
01-13-2010, 01:06 AM   #18
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There is this Pentax in the Marketplace. - https://www.pentaxforums.com/forums/photographic-equipment-sale/86204-sale-pe...100-300mm.html
01-13-2010, 06:55 AM   #19
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I saw that one Gary. Right now though I can't buy anything. I'll have to sell some lenses and a camera, then add money to that to be able to buy.

01-13-2010, 09:28 AM   #20
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QuoteOriginally posted by Damn Brit Quote
Is that really a better lens than her Sigma 70-300mm APO? It seems to be rated pretty low in the lens review section.
01-13-2010, 09:33 AM   #21
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QuoteOriginally posted by photolady Quote
I'll have to sell some lenses and a camera, then add money to that to be able to buy.
Are you sure you're getting all you can out of the Sigma? I've seen some pretty impressive photos from that lens. Shooting at 4500mm equivalent with a slow consumer-grade lens is no easy thing, it requires good technique and some practice. Maybe you just need to keep practicing and improve on your post-processing skills. It's amazing what even a free and easy to use program like Picasa 3 can do for sharpness. colour and contrast. If all you have so far is the Pentax supplied software, I highly recommend you give Picasa a try. Picasa 3: Free download from Google
01-13-2010, 10:00 AM   #22
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I have Photoshop Elements, and Photoshop. I have the pentax software installed, tried it once and never used it again. I also have Faststone Image viewer which I use more often than either Adobe product. I use the Adobe's to tweak the photos but use Faststone to view them.

I guess I just need more practise with this lens. I owned the F100-300mm at one time and it seemed to work ok, then though I was using film cameras, a K1000 and a MZ-5n. My photos were sharp using this lens with those cameras. Course I never used it on autofocus.
01-13-2010, 10:20 AM   #23
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QuoteOriginally posted by photolady Quote
I have Photoshop Elements, and Photoshop. I have the pentax software installed, tried it once and never used it again. I also have Faststone Image viewer which I use more often than either Adobe product. I use the Adobe's to tweak the photos but use Faststone to view them.
Wow, I assumed that since you've just gotten into digital that you wouldn't be so well outfitted. Were you scanning and processing your film photos too?

QuoteOriginally posted by photolady Quote
I guess I just need more practise with this lens. I owned the F100-300mm at one time and it seemed to work ok, then though I was using film cameras, a K1000 and a MZ-5n. My photos were sharp using this lens with those cameras. Course I never used it on autofocus.
Don't forget that on film it's a 300mm, on digital it's 450mm equivalent. Also, computer monitors encourage pixel peeping a lot more than prints do. Have you tested your Sigma for correct focus and/or decentering? Maybe your lens isn't up to scratch?

01-13-2010, 12:46 PM   #24
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I have been shooting since 1995 when I bought my first K1000. I've been scanning negatives since about that time also. I've used Photoshop since version 2.5. I don't scan photos, I scan negatives and slides.

No, I didn't know the equivalent was 450mm on a digital. My monitor is a 22" Samsung LCD. I don't know what you mean about correct focus. I though all lenses were correctly focusing. And what do you mean by decentering? Never heard of that.
01-13-2010, 12:55 PM   #25
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QuoteOriginally posted by photolady Quote
No, I didn't know the equivalent was 450mm on a digital.
Would you suggest you Google the term "crop factor", and then be prepared to read through lots and lots of stuff and go through a period of being highly confused before finally realizing it's a pretty simple concept: a lens of a given focal length on your DSLR will provide the same field of view as a lens 1.5 times that focal length on your 35mm film camera.

QuoteQuote:
I don't know what you mean about correct focus. I though all lenses were correctly focusing.
Sure, in theory, but defects exist. Sometimes they are very real, sometimes it is just a case of people obsessing about tiny discrepancies, other times people mistaking their own errors for lens or camera problems. Basically, not worth worrying about for most people. If you happen you to have a defective lens, you'll figure it out eventually. If you aren't already an expert in these amtters, most attempts to test for defects end up finding problems that aren't there do to incorrect testing methods..

QuoteQuote:
And what do you mean by decentering? Never heard of that.
Google has - search for "lens decentering". Just another type of potential lens defect not worth worrying about for most people.
01-13-2010, 12:57 PM   #26
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QuoteOriginally posted by photolady Quote
I have been shooting since 1995 when I bought my first K1000. I've been scanning negatives since about that time also. I've used Photoshop since version 2.5. I don't scan photos, I scan negatives and slides.
That's all new to me. I only ever printed my films or showed them on a projector.

QuoteOriginally posted by photolady Quote
No, I didn't know the equivalent was 450mm on a digital. My monitor is a 22" Samsung LCD. I don't know what you mean about correct focus. I though all lenses were correctly focusing. And what do you mean by decentering? Never heard of that.
Because of crop factor, the fov changes for all your lenses when used on an APS-C. (IOW, if it's set for 300mm on your K1000, it will be 450mm on your K100D).

Unfortunately not all lenses focus properly. Some routinely back or front-focus. That's why the K20D and K-7 allow calibration of individual lenses. Decentering is another lens defect, where maximum sharpness is not in the center. You can check for these defects by shooting a page of newsprint.

Last edited by audiobomber; 01-13-2010 at 01:14 PM.
01-13-2010, 01:06 PM   #27
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QuoteQuote:
I think most people put the Signa 70-300 dead last among the major contenders (DA55-300, Tamron 70-300, DA50-200) when it comes to sharpness. If the 55-300 even used is too much, the Tamron 70-300 would be the next logical contender if you need 300mm, although you'll trade some CA for that extra sharpness.
Photo.do (?), for what it's worth, ranked the Sigma APO version as the only 70-300 budget zoom worth getting a couple years back. Go figure...

I found that if you bump the contrast way up, things look much better. I did side-by-side shots of the Sigma vs the Pentax 50-200 over the same focal length and the Pentax was only minutely better due to the snappier contrast.

Many people like the Tamron and it's certainly cheap enough. The Pentax 55-300 is way nicer than the Sigma 70-300 or Pentax 50-200, though the fringe is blue, not purple....

One aperture blade died on my Sigma, but I had already retired that, and the 50-200, after getting the Pentax 55-300.
01-13-2010, 05:10 PM   #28
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Honestly, save yourself enormous grief and sell all your lenses and get the 18-55 and 50-200 (or Tamron 70-300 if you must). Keep the Raynox and maybe pick up a cheap MF 50 so you have a fast leans.

it won't cost you a penny.

Right now your lenses are a mishmash that don't work real well on digital from a FOV perspective. Did you not notice lenses had a VERY field of view when you put them on the 100D?

It's like night and day compared to film, it's way, way tighter.
01-13-2010, 06:49 PM   #29
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Marc thanks for the comments. I did google "lens decentering" and read a few articles and still not sure what they mean and figured as you said, it's just not worth worrying about.

I guess I won't know for sure if this lens is focusing properly or not until I have done more practising with it and/or get another lens.

Marc and Dan: As for "crop factor" I think we discussed this before in on of my other threads on using DSLRs compared to Film cameras. But if that's true why doesn't the actual focal length show up in EXIF details? Course I have noticed that this says "310" when the camera is set on 300. Is that a problem?

SpecialK thanks for the comments.

Alfisti, I could do that, but three of those lenses were given to me and I wouldn't know what to charge for them. One was just recently given to me by a member here and it would make me feel ungrateful if I turned around and sold that same lens here on the forum.

And when I got these lenses, I wasn't even thinking going digital. So they were just what I needed.
01-13-2010, 07:04 PM   #30
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QuoteOriginally posted by Alfisti Quote
Right now your lenses are a mishmash that don't work real well on digital from a FOV perspective.
AFAIC, 28, 50 and 135mm is a very good fov selection, just lacking something wide. I agree, a kit lens would be a good addition, or 16-45mm, or virtually any wide angle. I'd be a lot more concerned with plugging that hole than trying to improve at the long end.
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