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06-06-2012, 11:31 AM   #16
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QuoteOriginally posted by top-quark Quote
A macro lens is one that's designed to focus very close-up and offer good performance right across the frame. That again is difficult to achieve which is why you generally don't find macro lenses faster than F2.8.*
Are you refering to tests or from experience.
Often the problem is that the field is curved so if you shoot a flat taget like a test chart and focus on the middle the corners will be simply out of focus, with normal lenses the width of the DOF is often enough to correct that but not with fast lenses.

Macro lenses are make to specially have a flat DOF, that's why they preform so good in such tests.

06-06-2012, 11:33 AM - 1 Like   #17
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Others here have done a great job answering the "Why are cheap zoom lenses not also fixed wide aperture lenses" question.

To speak to your comment about being done reading for a little while... listen to your own advice. Shoot first and ask questions later. Pick one of your recently acquired lenses and go shoot everything you can find with it for like a week. If the subject will hold still, shoot it with a ton of different settings. You will learn what the settings do because your camera will teach you... The image results will teach you... This is the beauty of digital. Then, browse around the galleries here or jump on flickr and start to find images that have a look and feel you like. Check the Exif data for those images so you learn the settings that were used, read the poster's comments on how they composed it, set it up, whatever... THEN, start a couple threads like "I tried to make an image like this one... but instead I got this...". With images to look at, tons of folks here will offer advice to get you pointed in the right direction.

I look forward to seeing the pictures you post!
06-06-2012, 12:00 PM   #18
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QuoteOriginally posted by Anvh Quote
Are you refering to tests or from experience.
Bit of both. 35 Ltd. and Tamron 90. Both quite excellent.

As you point out, macro lenses tend to perform well in test-chart-type tests too because of the lack of field curvature. Tamron have just done an F2 macro come to think of it (not for us, though). I'll be interested to read how that performs.
06-06-2012, 12:17 PM - 1 Like   #19
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I saw a number of questions in the original post I didn't see answered directly (although I may have missed it), so:

QuoteOriginally posted by alamo5000 Quote
Maybe I am incorrect but I am directly correlating bokeh capability to the f.stop numbers...
The term "bokeh" refers to the *quality* of the out of focus area, not the *quantity*. The quantity of out of focus area does indeed depend on aperture (also focal length and/or shooting distance), and is measured as "depth of field". More DOF means less is out of focus, and that comes from small aperture (large f-numbers); less DOF means more is out of focus, and that comes from larger apertures (small f-numbers). But "bokeh" is how you compare to images at the *same* DOF - which one renders the out of focus areas more pleasingly, in someone's laregly subjective determination.

QuoteQuote:
I have a 28mm f 2.8 but I find that lens only creates marginal bokeh.
Translation: f/2.8 does not create very shallow DOF at 28mm, whereas it does at 100mm. But the *quality* of the bokeh is another matter.

QuoteQuote:
If I could go the other direction too... say a 28mm lens with a 1.4 or 1.8 or whatever the best I can get in manual lenses...
They exist, and do give shallower DOF than a 28/2.8, but these lenses are not known for the stellar *quality* of their bokeh.

QuoteQuote:
I have even heard of people using macro lenses to take regular pictures with...for the exact reason I am talking about...

I have never laid hands on a macro lens so I don't know what's different about those...
Nothing that is relevant here. You are mistaken if you think people take regular pictures with macro lenses for this specific reason. They do so becuase a macro lens is not fundamentally different from a regular lens and can thus do everything a regular lens can do, so why *not* use them to take regular pictures? The only significant difference between a macro and non-macro lens is that the former allows you to focus from closer. It might happen that any given macro lenses might also have nice bokeh, but it won't have any shallower a DOF than a non-macro lens, and there is no special reason macro lenses would have better bokeh for the same aperture. Although the D-FA100/2.8WR does have rounded aperture blades - that is a factor that affects the quality (not quantity) of bokeh in a good way. There are non-macro lenses that have rounded aperture blades too, though.

QuoteQuote:
For example if you look at Pentax's website they have a 300mm fixed lens that has a f4 to an f 32 range... its all auto...why can't they put an f 2.0 on a lens like that????
1. price
2. size
3. weight

A 300/2 would be the size and weight of a 15 pound sack of potatoes and cost about as much as not just one but *two* brand new Honda Civics. See the 300/2 Nikon once made:

Nikon F 300/2

06-06-2012, 01:10 PM   #20
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QuoteOriginally posted by top-quark Quote
Bit of both. 35 Ltd. and Tamron 90. Both quite excellent.

As you point out, macro lenses tend to perform well in test-chart-type tests too because of the lack of field curvature. Tamron have just done an F2 macro come to think of it (not for us, though). I'll be interested to read how that performs.
Zeiss has a 100mm f/2 macro for some time, it preforms very good i've read and there is Voigtlander APO-Lanthar 125mm f/2.5 which also a macro and that one has very nice Bokeh.
Voigtlander 125mm f/2.5 Macro APO-Lanthar sample pics topic
06-06-2012, 03:09 PM   #21
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QuoteOriginally posted by Marc Sabatella Quote
A 300/2 would be the size and weight of a 15 pound sack of potatoes and cost about as much as not just one but *two* brand new Honda Civics. See the 300/2 Nikon once made:

Nikon F 300/2

That thing won't fit in my camera bag.

Also thank you all for putting up with my amateurish questions....
06-06-2012, 03:19 PM   #22
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QuoteOriginally posted by Davidw0815 Quote
I think you have to learn about the relationship between focal length, aperture and depth of field (read!) and try out what you've learn. All the equipment won't make you a better photographer if you don't know your basics. It's much better to work with what you've got than keep thinking what you might need.
To get an idea what 'even' with a kit lens is possible: PENTAX : Select a PENTAX interchangeable lens camera or a lens model
DUDE.

You are so right on.

Honestly you are echoing what I already think....This is my first DSLR and honestly I am new to this stuff....I read a whole ton before I ever bought any camera and ended up getting the K-5....

Now that I have the K-5 I am learning that I need to learn more LOL!

My questions are just becoming more technical (and different) than they were a year ago...back then I didn't even own a dslr...

I have only owned my camera a few weeks...but I read a bunch before I ever bought.

I have a friend who is a famous photographer and I grilled him left and right about what gear he uses and this and that... his response?

"It would be like going to eat at someone's house and having a fabulous meal and then commenting...."you must have some wonderful pots and pans""

I am just shooting in the dark with my questions as I encounter things from sheer old fashioned trial and error.

You didn't see my original posts on here where I expressed a desire to 'know' and to be a 'technical shooter'...what's in your brain is more valuable than what's in your camera bag....(I mean if you know anything at all that is)....
06-06-2012, 06:19 PM   #23
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QuoteOriginally posted by Anvh Quote

About f-number well it's a ratio between focal length and lens opening.
It's focal length divided by the iris opening
If you want f2 100mm lens the iris opening needs to be 50mm
if you want f4 100mm the iris opening is 25mm
So with your 300mm f/2 you need 150mm, you see the problem beside that the lens mount has a fixed diameter and that opening also needs to be taken into account.

With cheaper zooms the lens opening doesn't change enough to keep the f-ratio constant, when you zoom your lens from 100mm to 300mm the opening needs to be 3 times as large as well for example
Excellent!!!

06-06-2012, 06:26 PM   #24
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QuoteOriginally posted by Davidw0815 Quote
I think you have to learn about the relationship between focal length, aperture and depth of field (read!) and try out what you've learn. All the equipment won't make you a better photographer if you don't know your basics. It's much better to work with what you've got than keep thinking what you might need.
To get an idea what 'even' with a kit lens is possible: PENTAX : Select a PENTAX interchangeable lens camera or a lens model
David...You mention basics.... I thought I understood some basics but that was before I bought a camera!

My basics were more about actual equipment and this or that, but in all honesty not so much about technique.

If you were to recomend some good topics about 'basics' what would they be?

I will google and look them up and so forth... I am talking moving my discussion from an 'equipment discussion' to a skills discussion...

In fact that goes for anyone.... any topics that you feel are 'must know info'????
06-06-2012, 06:31 PM   #25
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QuoteOriginally posted by HockeyDad Quote
Others here have done a great job answering the "Why are cheap zoom lenses not also fixed wide aperture lenses" question.

To speak to your comment about being done reading for a little while... listen to your own advice. Shoot first and ask questions later. Pick one of your recently acquired lenses and go shoot everything you can find with it for like a week. If the subject will hold still, shoot it with a ton of different settings. You will learn what the settings do because your camera will teach you... The image results will teach you... This is the beauty of digital. Then, browse around the galleries here or jump on flickr and start to find images that have a look and feel you like. Check the Exif data for those images so you learn the settings that were used, read the poster's comments on how they composed it, set it up, whatever... THEN, start a couple threads like "I tried to make an image like this one... but instead I got this...". With images to look at, tons of folks here will offer advice to get you pointed in the right direction.

I look forward to seeing the pictures you post!
Excellent advice.

This has been an extremely informative thread for me at least....
06-06-2012, 07:06 PM   #26
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QuoteOriginally posted by alamo5000 Quote
David...You mention basics.... I thought I understood some basics but that was before I bought a camera!

My basics were more about actual equipment and this or that, but in all honesty not so much about technique.

If you were to recomend some good topics about 'basics' what would they be?

I will google and look them up and so forth... I am talking moving my discussion from an 'equipment discussion' to a skills discussion...

In fact that goes for anyone.... any topics that you feel are 'must know info'????

Rather than relying on random "shot in the dark" questions or googiling fragmentary information, why don't you invest in a photography book? You will find that in a good book the basics are presented clearly and systematically. I'd say that is the real "must know info" for someone at your level.
06-06-2012, 07:08 PM   #27
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QuoteOriginally posted by alamo5000 Quote
Maybe I am incorrect but I am directly correlating bokeh capability to the f.stop numbers...But I would specifically want those lenses so that I have the broadest range of apertures on my lenses all at different mm focal lengths. And if they are manual lenses I turn that aperture ring to 2.8 @ 100mm (as an example) then I can adjust the other stuff as needed...
One of the most important features of Bokeh is the size of an out-of-focus pinpoint of light. The other feature is the character of the blur which I won't talk about here.

It turns out that the maximum blur diameter is proportional to absolute aperture of the lens, F/N

Blur.diameter.max = (sensor.width/scene.width)(F/N).

The important thing here is that a lens' effect on the size of an out-of-focus dot depends only on the F/N ratio used for the photo.

Dave in Iowa

Last edited by newarts; 06-07-2012 at 07:32 AM.
06-06-2012, 07:19 PM   #28
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QuoteOriginally posted by John Poirier Quote
Rather than relying on random "shot in the dark" questions or googiling fragmentary information, why don't you invest in a photography book? You will find that in a good book the basics are presented clearly and systematically. I'd say that is the real "must know info" for someone at your level.
I have about 4 or 5 books....I read through all of them over the course of time...I will give it a shot to look back at them again with fresh eyes.

You see, when I read the books the first time I was reading it from the perspective to find out what kind of stuff to buy so that I could be in the game at all...

I wanted to get something (equipment wise) that would allow me on the field of play...

Now that I have the basic tools though reading those books with a different angle on what I am trying to gain from it might proove to be very helpful...

Some of this stuff is so technical on my first reading I wasn't reading with that stuff in mind...I was primarily referencing information for what I was looking for at the time...

In ways I feel overwhelmed. I am trying to absorb 20 years worth of expertise by reading a book over a period of a few weeks or a month.

The thing is now that I have a camera--when I read something I can actually go out and experiment with the concept....
06-06-2012, 08:27 PM   #29
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QuoteOriginally posted by alamo5000 Quote
I have about 4 or 5 books....I read through all of them over the course of time...I will give it a shot to look back at them again with fresh eyes.

You see, when I read the books the first time I was reading it from the perspective to find out what kind of stuff to buy so that I could be in the game at all...

I wanted to get something (equipment wise) that would allow me on the field of play...

Now that I have the basic tools though reading those books with a different angle on what I am trying to gain from it might proove to be very helpful...

Some of this stuff is so technical on my first reading I wasn't reading with that stuff in mind...I was primarily referencing information for what I was looking for at the time...

In ways I feel overwhelmed. I am trying to absorb 20 years worth of expertise by reading a book over a period of a few weeks or a month.

The thing is now that I have a camera--when I read something I can actually go out and experiment with the concept....
I think you're on the right track. Just take your time and don't try to learn everything at once. Remember you can go back and forth between books and experiments repeatedly until things make sense.
06-06-2012, 11:51 PM   #30
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QuoteOriginally posted by alamo5000 Quote
David...You mention basics.... I thought I understood some basics but that was before I bought a camera! My basics were more about actual equipment and this or that, but in all honesty not so much about technique. If you were to recomend some good topics about 'basics' what would they be? I will google and look them up and so forth... I am talking moving my discussion from an 'equipment discussion' to a skills discussion... In fact that goes for anyone.... any topics that you feel are 'must know info'????
Well, the goal is that you are able that you get from an idea to an image. Therefore you have to know your camera...
With basics I mean things like:
-What does the aperture do and how does it affect the exposure time?
-The relationship between aperture and DOF
-Perspective/distortion
-How do I get the exposure right?
-...
Well, it's kind of hard to give you advice on such a general level. I'd recommend that you pick a topic (like bokeh) and get out and try. In the case of bokeh you could pick a subject and try to separate it from its background. Try different apertures and lenses. If your lens doesn't allow automatic aperture control, note the aperture setting for each image, so that you know what you did when you check your images on the computer. Critically examine your image in 100 % view.
If have any specific question, post the photo in the 'photo critique' section and you'll get help.
And look at pictures of others. On this forum you have the great opportunity to get in touch with other photographers. So if you see an image you like and wonder how it was done, just ask...
Hope I could help you a little bit.
Cheers,
David
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