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03-02-2009, 03:46 PM   #16
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Well, the DA40 is a FF lens, because it shares the same optical design as the M40.

I have seen pictures taken by the DA40 mounted on a film body. I am sure if you pixel peep, there will be some decline in corner sharpness. But given how well the DA40 performs across the frame on APS sensor, I don't expect it would behave quite as bad as that Sigma.


QuoteOriginally posted by Gooshin Quote
if the DA40 was built to cover a full frame image circle, it would cost more money

if it was built to cover a FF image circle, and maintained its comperative edge to edge sharpness, it would cost alot more money.

the DA40 is cheap because it is designed for APS-C (well that and because its f2.8, requiring smaller glass, making the QC better)


03-02-2009, 03:47 PM   #17
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QuoteOriginally posted by cousinsane Quote
Well, the DA40 is a FF lens, because it shares the same optical design as the M40.

I have seen pictures taken by the DA40 mounted on a film body. I am sure if you pixel peep, there will be some decline in corner sharpness. But given how well the DA40 performs across the frame on APS sensor, I don't expect it would behave quite as bad as that Sigma.
sorry then, must have missed that, i was under the impression that all of the DA pancake lenses were doomed on FF.

i'll look into that.

according to this fella the corners are soft (and its somewhat noticable, although the pics he took were not the best for that sort of showing)

http://forums.dpreview.com/forums/read.asp?forum=1036&message=26643607
03-02-2009, 03:50 PM   #18
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Also, I've shot my DA70 on film. To my eyes, it works just fine.


QuoteOriginally posted by Gooshin Quote
sorry then, must have missed that, i was under the impression that all of the DA pancake lenses were doomed on FF.

i'll look into that.
03-02-2009, 03:53 PM   #19
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QuoteOriginally posted by cousinsane Quote
Also, I've shot my DA70 on film. To my eyes, it works just fine.

the propostion then is the FA77 better on FF than a DA70?


again i'm only pointing out the deficiencies of lenses, in general, when mounted on different formats.

As i have taken to film for the time being, i am finding many lenses i liked on my K20D to be mediocre on film.

i am also very glad i never sold my FA43.

03-02-2009, 06:16 PM   #20
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QuoteOriginally posted by Gooshin Quote
if the DA40 was built to cover a full frame image circle, it would cost more money

if it was built to cover a FF image circle, and maintained its comperative edge to edge sharpness, it would cost alot more money.

the DA40 is cheap because it is designed for APS-C (well that and because its f2.8, requiring smaller glass, making the QC better)
There is no truth in this assertion. FF won't cost more money
but requires merely a redesign of the rear group to cover the wider image circle.

QuoteOriginally posted by cousinsane Quote
Well, the DA40 is a FF lens, because it shares the same optical design as the M40.
....
While the DA can be used to cover a FF image circle, nonetheless
there are small differences between the DA and M versions of the 40mm.
Here are some test images:
【伊達淳一のレンズが欲しいッ!】ペンタックス smc PENTAX-DA 40mm F2.8 Limited
03-02-2009, 06:21 PM   #21
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QuoteOriginally posted by Gooshin Quote
Which i think everyone should keep in mind when talkinga bout Pentax's current DA lineup of glass. Its much easier to make optics that cover a small image circle with edge to edge perfection.
Better than just speculation about Pentax DAs based on a Sigma 18mm, how about actual images of DA lenses on full frame.

DA Lens Full Frame: Test Shots

The thread includes lenses other than Pentax.

Last edited by wasser; 03-02-2009 at 06:38 PM. Reason: fixed url
03-02-2009, 06:41 PM   #22
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No real comment.....

The photo presented is certainly soft at the edges, and I'll take your word for it as for the reason, I am not much of a "tester".
I do agree that the best lenses I own are also, for the most part, the most expensive, and I assume that IQ is in the formula of pricing, so I am not too surprised.
Now for a question for someone that is more of a "tester" than I am. I have several Pentax 645 lenses and have heard references to them providing a better edge sharpness on my K20D due to the size in relationship to the sensor. I have been very happy with the 645 performance on my K20D but have not done and specific testing for edge sharpness. Has anyone? Is this a valid point? I do know that just holding a 645 lens in my hands is a thrill, the craftsmanship is superb, and the IQ has been delightful for my use. The A120 Macro is my favorite, followed by the FA45-85.
One from the A120 645 Macro lens
03-02-2009, 09:34 PM   #23
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QuoteQuote:
I'm probably not explaining myself very well. What I meant (in general, I have not experimented with this) is this:

A) FA+full frame = edge softness potential
B) DA+APS-C = edge softness potential
C) FA+APS-C = less edge softness potential

Therefore (in general) A=B, and A>C.

C is true because, as you and others have said, the APS-C sensor is only using the "sweet spot" of the lens, and any edge softness falls outside the boundaries of the sensor.

Again, I'm just speaking in generalities, so feel free to point out where/how I'm mistaken.
I think you explained yourself very well, and I love Aristotelian logic too--which is what your A, B & C demonstration is. What you say makes complete sense. Taking your discussion up one step, we can talk about Medium Format lenses:

D) Medium Format on crop sensor= even less potential for any edge softness

And we could move into large format discussion too.

03-02-2009, 09:42 PM   #24
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QuoteQuote:
Rupert: Now for a question for someone that is more of a "tester" than I am. I have several Pentax 645 lenses and have heard references to them providing a better edge sharpness on my K20D due to the size in relationship to the sensor. I have been very happy with the 645 performance on my K20D but have not done and specific testing for edge sharpness
.

I have done some testing here https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/49428-medium-f...20-sensor.html of Medium Format 67 lenses on the K20d. There are some test images presented deeper in the thread. While the test was not geared specifically for edge sharpness, there can be little doubt MF lenses on the Pentax crop sensor yield images unparalleled in evenness.

I am still testing on my own and look forward to presenting more tests.
03-02-2009, 09:43 PM   #25
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I've shot a roll of film with the DA 40mm. Worked fine. But I am not that demanding.
03-02-2009, 09:44 PM   #26
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Roentarre: this is a hobby to obsess oneself in anything trivial.

Well said, indeed!
03-02-2009, 09:55 PM   #27
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QuoteQuote:
Benedict: Sometimes it is amazing, what the industry tries to sell - and I bet, there are enough happy snappers using the lens and finding the images very good "considering the price", which is a lame excuse for crap.

Ben
But Ben, we all know the industry doesn't make anything it can't sell. A product's worth is solely reliant upon the demand of the market.

For example, fast food sells, even though mostly everyone knows it is not good for them. But people are in a hurry and the food is temporarily satisfying. And clearly our bodies should get more of our attention and money than our camera bodies--right?

What I'm getting at is not everyone, in fact few for that matter, have the resources to spend $1500 on a lens. Some people do not spend that on a car. It is not so much that people are happy with junk on their camera (though they may be happy with junk in their bodies); rather, it is that people MUST be happy with less than the best on their cameras because they have priorities: mortgages; car payments; insurances; medical bills; college educations and so on.

If people can find joy in the images their $140 lens produces then all the power to them!
03-02-2009, 10:13 PM   #28
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QuoteOriginally posted by Jewelltrail Quote
But Ben, we all know the industry doesn't make anything it can't sell. A product's worth is solely reliant upon the demand of the market.

For example, fast food sells, even though mostly everyone knows it is not good for them. But people are in a hurry and the food is temporarily satisfying. And clearly our bodies should get more of our attention and money than our camera bodies--right?

What I'm getting at is not everyone, in fact few for that matter, have the resources to spend $1500 on a lens. Some people do not spend that on a car. It is not so much that people are happy with junk on their camera (though they may be happy with junk in their bodies); rather, it is that people MUST be happy with less than the best on their cameras because they have priorities: mortgages; car payments; insurances; medical bills; college educations and so on.

If people can find joy in the images their $140 lens produces then all the power to them!
I pretty much have to agree with that philosophy. Although I covet fine glass, and superb IQ (without a huge success rate for sure) I also find that some of my best images and most viewed photos fall very short in most areas we would judge here. It is that same old "Beauty is in the eye..........." It is certainly not necessary to have the finest glass to make outstanding photos, sometimes the emotions in a shot outweigh everything else.
03-02-2009, 11:05 PM   #29
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QuoteQuote:
wildman "Why some lenses are worth the price."

I think it's a much more interesting and difficult question to ask why some lenses are not worth the price.


QuoteQuote:
okay then start your own thread, durr.

thanks for crapping in mine with an open ended question leaving behind a trail of confusion and anxiety.

Also, i wasnt asking, i was telling, my observations...
Gooshin, to be fair--Wildman has a good point. After all, your pic shows a technically bad image i.e., an example of why some images are "not worth the price." You are yet to produce an image that shows why some images ARE WORTH the price. It appears Wildman had more aptly entitled your thread than you have.



Your turn.........................................
03-03-2009, 02:43 AM   #30
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QuoteOriginally posted by Rupert Quote
I pretty much have to agree with that philosophy. Although I covet fine glass, and superb IQ (without a huge success rate for sure) I also find that some of my best images and most viewed photos fall very short in most areas we would judge here. It is that same old "Beauty is in the eye..........." It is certainly not necessary to have the finest glass to make outstanding photos, sometimes the emotions in a shot outweigh everything else.
I agree, that you don't need the best glass to make compelling photographs. At last it is the photographer, who makes the image. Nevertheless any good image is compromised, if the technical quality is poor. And if you earn money with photography (or at least if you try to), then technical perfection is the basis on which to build your business. I am not refering to those highly valued family snapshots etc. This is a different story, which does not bother me personally, as here anything goes, as long as the viewers are happy. This would be more about sentiments, than about photography.

Ben
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