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How is this possible? (Depth of field question)


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Posted by mlife
Okay... so I shoot with my 808 pureview pretty frequently and I love to try and "reproduce" great image I see just to challenge myself but I'm just baffled by this image.



At first I was like WOW, amazing.. but then when I started to think about the 808's 1/1.2 sensor, it would only make the shallowest depth of field possible similar to what a 26mm lens set to f/8 on a 35mm or "full frame" camera/sensor could produce. Using those numbers it seemed bizarre to me that such a shallow depth of field was even possible at f/8.... ?? not to mention that in the sample image only about half the eye is in focus and the eye FILLS the frame + the image is taken in 8mp mode according to the EXIF data.... but have you ever tried to focus on JUST someone's eye in 8mp mode on your 808? doesn't exactly fill the frame not to mention you have depth of field greater that a 1/2 inch or so PLUS....

So, I started to try and duplicate the image based on what I could see while also keeping in mind that the eye is filling the frame in 8mp mode. But when I started taking images with my 808, I realized that the closest I was getting to my subjects eye was only allowing me to fill about a 1/4 or 1/5 of the frame. After that, I realized that I probably need to multiply the focal length by a power of at least 4 (maybe 5) or get MUCH MUCH CLOSER to the subject somehow in order to get the same "look" as the sample image. After not being able to reproduce the image with just my 808, I started using a additional lens in front of my 808's lens to allow it to focus closer (as close as 2in with a lens removed from a loupe) but I just couldn't get anything even similar don's image...

Next, I started to use a 200mm f/2 lens mounted via an extension tube and connected to a FF dslr to come even close..... I'm sure other combinations would work but this seemed to produce the "closest" result. The image below wasn't shot using an 808 but look how similar it is to don's 808 image (and he created his with the 808)



This leads me to believe I am either missing something regarding the technique used here with the 808 or this user is somehow altering their EXIF data.... but why bother? I don't want to accuse anyone of anything but would love to figure out what is going on here...

any input? or if don_gori wouldn't mind stopping in to give a tutorial of how is image was done, that would be awesome.
[ This Message was edited by: mlife on 2013-08-04 21:38 ]



Posted by alenn
He probably stacked a small lens element on the 808's lens.
Maybe he cropped / zoomed the shot.
It's not full size.

Posted by hihihans
Maybe the image is cropped.
Wonderfull shots, you can look right through the eye.
Did you try to PM him and ask.


Posted by mlife

On 2013-08-04 18:14:54, alenn wrote:
He probably stacked a small lens element on the 808's lens.
Maybe he cropped / zoomed the shot.
It's not full size.



I tried that with several different lenses.... couldn't duplicate it.

Posted by mlife

On 2013-08-04 18:20:09, hihihans wrote:
Maybe the image is cropped.
Wonderfull shots, you can look right through the eye.
Did you try to PM him and ask.




tried that too... shot full 38mp image and cropped down to the exact dimensions of the 808's 8mp image but that still does not change the depth of field. Tried using the 3mp mode and stretching the image out to 8mp dimensions but same exact image.... because you are not optically zooming, it appears the effect is not manageable from the 808 which is why I'm so baffled.

yes... last month I sent a pm which was never replied to (hence the reason for this post).

I'd love to know how it did it... the image gives a DSLR look to an 808 image... I must know how it was done!

Posted by hihihans
Must be just a lucky once in a lifetime shot

don_gori makes good photos but this one really stands out.

Posted by mlife

On 2013-08-04 20:57:40, hihihans wrote:
Must be just a lucky once in a lifetime shot



LMAO.... LUCK is an understatement but I believe ultimately has nothing to do with this image... the physical capability of a camera in regards to depth of field is a VERY hard-fast rule which can be easily calculated while using known specifications. This picture has however defied those rules and Im just curious to hear a verifiable (duplicatable) explanation as to how it was accomplished. If it is done with a lens (as I originally suspected), I would just LOVE to know which he used and where to get one!!


NO DOUBT that don_gori makes great images... I am however in doubt that they are made with the 808 (unless some gobo or post processing is involved).
[ This Message was edited by: mlife on 2013-08-04 21:44 ]


Posted by cu015170
Most likely a magnifying glass of some sort

Posted by mlife

On 2013-08-06 04:19:03, cu015170 wrote:
Most likely a magnifying glass of some sort


Based on the vignetting on the right side of the frame, my two best guesses are;

-by holding a large aperture slr lens in front of the 808 which is not perfectly in line with the 808's element.
-or a small loupe or magnifying glass.

brilliant shot either way, now more just curious to see the set up.


Posted by mlife
WooHoo.... found just the right element....



The little lens in that picture is something I have had sitting around for quite some time. I decided to hold it directly in front of the 808 lens and it worked exactly as I was hoping. Seems that the magnification was increased by about 10 and depth of field dramatically reduced. There was no one home today for eyeball pictures so I used some coins I had in a drawer....



.... depth of field SO SHALLOW that not even half the coin is in focus. I need to get out side and play with this combo a bit.
[ This Message was edited by: mlife on 2013-08-10 14:22 ]


Posted by cu015170
That's it...

By the looks of it ... might be shallower than the one used for the eye photograph in question.

Posted by don_gori
Lens mate , first photo is mine , and i use just one simple lense to capture it


Posted by alenn
I knew it!
I have the same lens element in my room

Posted by hihihans
@don_gori, I think mlife wants to know all the details now; distance, angle, light, etc.

Posted by mlife

On 2013-08-11 11:49:00, hihihans wrote:
@don_gori, I think mlife wants to know all the details now; distance, angle, light, etc.



Actually at this point, I'm good... It was nice to see confirmation that it was just a lens used which I sort-of worked out on my own. I feel pretty comfortable at this point being able to reproduce such a shallow depth of field which was my primary goal.


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