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11-12-2006, 08:25 AM   #1
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What is the most important factor in choosing a lens?

Of course all the following things are important in buying a lens, but which one stands out the most when making a final decision?

darn the poll timed out before I could post it....

1) sharpness

2)CA

3)Bokeh

4)natural colors

5)vivid colors

6)size

7)speed

8)other please specify

thanks


Last edited by slip; 11-12-2006 at 08:39 AM. Reason: poll timed out before I could post it
11-12-2006, 11:55 AM   #2
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uhh, focal length?
11-12-2006, 04:47 PM   #3
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Cost.
(answer must be at least 10 long)
11-13-2006, 04:58 AM   #4
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I would go for vivid colour and wider aperture

After all, anything with * or limited.

11-13-2006, 04:29 PM   #5
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I believe "your needs" is the most important factor in choosing a lens. It is like you won't go out and buy a normal sedan as a family car for a family of 7 because you know it won't fit everyone in.

Once you've decided what you need, then you work out what compromise you are willing to make (eg speed vs weight, zoom (flexibility) vs prime (quality)). In other words, I don't think there is no one single answer to every lens you buy because reason/situation for buying a lens will be differerent every time. You might be restricted by budget when you first started but later on you might put more emphasis on quality, for example.

cheers
Kenny
12-11-2006, 07:26 AM   #6
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What's Bokeh and CA?

Anybody care to clarify please?
12-11-2006, 08:30 AM   #7
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QuoteOriginally posted by macopajuice Quote
Anybody care to clarify please?
bokeh is the amount and or quality of the blur that is produced with a lens. example a sharp subject with a blurred background.

CA is just anothe word for Purple fringing.... it is the artificial color that surrounds the outlines of certain subjects in a photo produced by a lens on a digital camera. it is usually only a few pixels wide, and usually with an area of bright contrast, and mostly purple in color (but not always)
less expensive lenses or poorly manufactured lenses tend to suffer more then high quality ones.

if I have missed anything others please let me know

randy
12-11-2006, 11:27 AM   #8
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macopajuice, randy, whoever:

QuoteOriginally posted by slipchuck Quote
bokeh is the amount and or quality of the blur that is produced with a lens. example a sharp subject with a blurred background.
Not amount, but quality. Thinking about it any piss poor lens can produce a huge lot of blur: it's just to set the focus way wrong.
When talking about quality of the OOF (Out Of Focus) areas it is obvious that it gets down to personal preferences. We are also talking about several different qualities: there are the OOF highlights, OOF areas in general, double lining (which is a special case of how the lens handles the OOF highlights) and also the look of the transitions from focused to OOF areas or objects. All these qualities are more or less impossible to measure. Still, we have a sort of definition of good and bad bokeh respectively when it comes to OOF highlights. Have a look at the hated and loved profile Ken R's place and his pages about bokeh:
Bokeh

You will find tons of pages about bokeh by a simple search. Remember that bakeh in general is highly depending on the combination of lens, aperture and the relation in distance between the subject in focus and the OOF areas. Tricky.

QuoteOriginally posted by slipchuck Quote
CA is just anothe word for Purple fringing.... it is the artificial color that surrounds the outlines of certain subjects in a photo produced by a lens on a digital camera. it is usually only a few pixels wide, and usually with an area of bright contrast, and mostly purple in color (but not always)
less expensive lenses or poorly manufactured lenses tend to suffer more then high quality ones.
if I have missed anything others please let me know
randy
CA (Chromatic aberration) can also be searched for. PF (purple fringe) is a simplified way to think about CA. CA itself can be seen in a variety of colors and it can be axial (causing so called "bokeh CA", halation and purple glow) or longitudinal (sagittal). For PF you can check a description at DPR:
Chromatic Aberration: Optical: Glossary: Learn: Digital Photography Review

Again, searching will reward you, and maybe drive you nuts.

Most Pentax lenses show some bright ring bokeh (defined as bad bokeh) but not to any large degree in my opinion. Sometimes it is disturbing though and a price you pay to get good resolution and lower CA. Some Pentax lenses produce a lot of CA (thinking of the A*84/1.4 and the A*135/1.8 for example) which sometimes ruins pictures. In other cases they can help you get totally awsome pictures. Bokeh is down to opinions and the same can be said about CA. Sometimes you see pictures that gets a lot of Oooh's and Aaah's but in my opinion suffers from bad bokeh or a lot of CA. Different entities reacts in different ways, or are more or less sensitive.

CA is not limited to digital. It can be seen with B&W film for example, as well. Then it is perceived as blur rather than color phenomens. Heck, you can see it in the viewfinder if you check for it.

What is sharpness?

Finally, I have to do the same as randy: "if I have missed anything others please let me know"

regards,

12-11-2006, 01:49 PM   #9
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all of the above
12-11-2006, 04:48 PM   #10
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For me, as a college student.

Price.

I wish it weren't, but it is. Plus, where it falls into the current line-up. I wouldn't buy 3 lenses at 18-55 if I don't have a 55-200 or even 300 range covered. So, really, in short, what I need to fulfill my lineup.
12-11-2006, 05:38 PM   #11
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Impossible to answer... I buy different lenses for different reasons... ;-)
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