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11-05-2009, 03:35 PM   #16
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BTW...

In case you are still interested in the idea of cropping...
https://www.pentaxforums.com/forums/mini-challenges-games-photo-stories/69199...r-pairs.html#2
Never mind that the cropped image was from the FA 77/1.8 Limited

Steve

11-05-2009, 04:07 PM   #17
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FSA43/1.9 is sharp enough for even 100% crops to work, this is a 100% crop and no downsizing with the K10D.



My close-up favorite is the F135/2.8, and with an ext. tube works well even without cropping. (used the flash so a little flat here)



But, the Tamron 90/2.8 macro is very decently priced and is a divine lens as well. You've got choices.
11-05-2009, 08:24 PM   #18
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For macro capabilities, the DA 35 can offer 1:1 magnification, you can focus extremely close, I am afraid I will bump the front element against my subject sometimes, it is also exquisitely sharp.

It also seems to remain sharp throughout the entire shot.



100% crop of the upper left corner

11-08-2009, 03:43 PM   #19
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Thanks to every one for their contributions, I am going to look for a good cheap 50mm and a Raynox 150 and see how I get on, also since the 150 can be used on a couple of other lenses I have with different focal lengths it occurs to me that I can then see what effect this will have on the distance I can be away from my subject.
Once that is established will probably look at a prime for that focal length, and later extension tubes.
many thanks to every one
Alistair from a wet and windy Bristol

11-08-2009, 04:19 PM   #20
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QuoteOriginally posted by adwb Quote
Thanks to every one for their contributions, I am going to look for a good cheap 50mm and a Raynox 150 and see how I get on, also since the 150 can be used on a couple of other lenses I have with different focal lengths it occurs to me that I can then see what effect this will have on the distance I can be away from my subject.
Once that is established will probably look at a prime for that focal length, and later extension tubes.
many thanks to every one
Alistair from a wet and windy Bristol
You may be a little disappointed in your desire to "see what effect this has on distance to the subject". When the main lens is focused at infinity the working distance (distance from the lens to the subject) it is simply the close-up lens' focal length, which in case of the Raynox 150 is about 8.2".

With the Raynox 150, you'll have a working distance of 8.2" minus a little due to in-out motion of the main lens when you turn the focusing ring for any focal length primary lens.

That is, the Raynox 150's maximum working distance is 8.2". Period. If you add a teleconverter to the front of the stack the working distance will still be about 8.2".

Maybe you should also consider buying a cheap set of focusing tubes now so you've got something to compare the Raynox with - they are like $7usd delivered these days on eBay. The 50mm lens plus 50mm of extension tubes will have a working distance of around 4" for 1:1 magnification.

With a close-up lens add-on what varies as you change the primary lens is the magnification, not the distance to the subject.

All that said, 8.2" is a reasonable working distance; about what you'd get with a 100mm macro lens at 1:1 magnification.

Last edited by newarts; 11-08-2009 at 04:34 PM.
11-08-2009, 04:50 PM   #21
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Using the term 100% crop is one of the most ambiguous terms in current usage. About the only thing that can be assessed when some one says that is that the image has been cropped.
11-08-2009, 05:38 PM   #22
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QuoteOriginally posted by Blue Quote
Using the term 100% crop is one of the most ambiguous terms in current usage. About the only thing that can be assessed when some one says that is that the image has been cropped.
I agree.

Out of curiosity, what term would you use?

Steve
11-08-2009, 05:55 PM   #23
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QuoteOriginally posted by stevebrot Quote
I agree.

Out of curiosity, what term would you use?

Steve
That's a good question and I don't have a good answer for it. I think a ratio of perhaps the area cropped out divided by the total original area would be 1 way.

11-08-2009, 06:17 PM   #24
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QuoteOriginally posted by stevebrot Quote
I agree.

Out of curiosity, what term would you use?

Steve
What about "crop of the full-sized image" - works for me!

Regards, Jim
11-08-2009, 06:25 PM   #25
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I think 100% crop is the proper term. Doesn't it mean, that the image is blown to 100% and then a crop taken out of it, and then that entire crop is posted. I don't know how the computer screen size affects this, but to me 100% crop seems the most appropriate.
11-08-2009, 06:30 PM   #26
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QuoteOriginally posted by pcarfan Quote
I think 100% crop is the proper term. Doesn't it mean, that the image is blown to 100% and then a crop taken out of it, and then that entire crop is posted. I don't know how the computer screen size affects this, but to me 100% crop seems the most appropriate.
The problem is that it could be 10% of the original 50% of the original or 85% of the original. Hence, it doesn't tell as much as some think other than some cropping occurred.
11-08-2009, 06:46 PM   #27
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A 100% crop has to be non-downsized . It is not just another crop.

When an image is posted as an original image at 100% resolution, then the whole image is visible at a certain size, now the 100% crop is just part of that image and the subjects within this crop will be the same size as the they were in the original image, as neither is downsized.

It really doesn't matter what percentage of the image the 100% crop is, as long as it is NOT downsized, then it has relevancy.
11-08-2009, 07:27 PM   #28
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QuoteOriginally posted by jamesk8752 Quote
What about "crop of the full-sized image" - works for me!

Regards, Jim
Let's hear it for precise language!

Steve
11-08-2009, 07:31 PM   #29
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QuoteOriginally posted by stevebrot Quote
Let's hear it for precise language!

Steve
"Crop of the image at capture resolution" ???


Arrrrgggg...
11-08-2009, 08:15 PM   #30
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QuoteOriginally posted by pcarfan Quote
. . .
It really doesn't matter what percentage of the image the 100% crop is, as long as it is NOT downsized, then it has relevancy.
For artistic purposes you can make that argument. For technical or scientific purposes, this is not true. That is why micrographs often have a scale on them.

Edit: As far as downsized images goes, it is still the entire image where a crop is not.
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