Daniel,
Truly, you have a dizzying intellect!!
All righty then. It's yardsticks at dawn!!
LOL!!
I'll post results tomorrow.
ITMT...............
Madison,
Do you have anyone who can help you? If not, I'd be willing to bet that you could finda museum employee to hold a reflector for you for five minutes.
Originally Posted by Chuck Lee
Wait till I get going!
...
Where was I?
Ah, yes: DOF. And you must have suspected I would have known the<span style="font-family: Century Gothic;"] DOF, so I can clearly not choose the wine in front of me.
[] I'll be there with bells on (and pocket protectors), but be warned: my character wields a +2 sword of nerdliness and +1 buckler of textbooks. [
]
....and a +12 year-old prophylactic, never used, apparently...
he he he
Daniel,
Your movie reference made me chuckle haha.
...wow I expected something much simpler like (focus on the nose and the eyes will be in focus if they are behint it and your aperture is narrow enough). I have DOF troubles with FF a bit, getting to grips with it. I honestly never shoot something this close and I never have focus issues with the camera or the lens but this monkey is trouble.
I thought. Small object. Stay close to minimum focus distance. Choose F8 to make SURE that everything is in focus (come on, its F8 and a small object, is what I thought) and shoot!
Shoot itw as. But it sounded slightly different than shoot when I said it.
I appreciate the (incredibly technical) DOf explanations but I have to be honest and say that I am having trouble understanding it for a number of reasons (all my fault). For one I have severe discalc (which means my brain somehow refuses anything to do with math, for real), I also don't understand inches (we are metric over here) and because English is not my native language when thinsg get this technical I am in way over my head.
I have a year subscription to the museum anyway so I will go back and figure it out with all the help here.
Not today though. Pooring cats, dogs and monkeys out there.
Wait till I get going!
...
Where was I?
Ah, yes: DOF. And you must have suspected I would have known the<span style="font-family:Century Gothic;"] DOF, so I can clearly not choose the wine in front of me.
Any thread on The-Digital-Picture.com that contains a Princess Bride reference I hereby propose automaticallybe placed in the Thread Hall of Fame. Because it's just THAT awesome.
DOF....you keep using that word. I do not think it means what you think it means.
I cannot contribute any technical information to this thread, so that's what you get.
R6 II --- RF 14-35mm f/4L IS --- RF 24-105mm f/4L IS --- RF 100-400mm F5.6-8 IS
70D --- EF-S 10-22mm f/3.5-4.5 --- EF-S 17-55mm f/2.8 IS --- EF 70-200mm f/4L IS --- EF 85mm f/1.8
You should be aware that the 24-105/4L IS has a "macro" focusing range that enables a maximum magnification of 0.23x. While that is not anywhere near 1:1 true macro (hence the use of quotes), it's quite respectable for a zoom lens of this design. So if you are really getting that close so as to fill the entire frame with this detail, you are losing a lot of DOF even at f/8.
If camera shake turns out not to be the overriding issue with respect to sharpness, you may be able to stop down to f/11 or f/16 to enable more forgiving DOF.
Daniel,
You only think I guessed wrong! That's what's so funny! I switched glasses when your back was turned! Ha ha! You fool! You fell victim to one of the classic blunders! The most famous is neverbuy a Hasselbladin Asia, but only slightly less well-known is this: never go in against Chuck when a opinion about DOF is on the line!! Ha ha ha ha ha ha ha!! Ha ha ha ha ha ha ha!! Ha ha ha-- I die laughing!!
Here's the test:
10ft was too far to get what I wanted so I back down to 6ft [1.83m] I did not have a "yardstick". Very strange. I can't ever remember in my life not having one in my house. Oh well,I used a tape measure instead. As stated in the earlier post I am taking one photo from 1) 3ft [.91m] 50mm @ f4 and two photos from 6ft [1.83m] 2) 100mm @ f4 & 3) 50mm @ f4. The 3rd photo is cropped to 1/2 of the size of the original image. All images were processed with SilkyPix, No sharpening, +.3ev adjustment on the 100mm f4 shot to match exposure. All images were developed @ 2184 x 1456 pixels which is 1/2 the native resolution of a 5D sensor and USM of 200, .6 was applied. Text was added in CS3 and 640 pixel reductions were created using bicubic sharper for display here. Distance to focus line was established by height to the tripod studplate vs. the linear distance from the stud to the focus line. 45 degree inclination resulted in 51" height x 72" hypotenuse and 25.5" x 36" for half distance. The reading of the tape measure at 3' and 6' simply confirm those setups and does not indicate some horizontal distance to the tripod.
Original Click Here
Original Click Here
Original Click Here
I have to admit that the last image wasn't exactly what I was looking for. The camera/lenssomewhat front focused. I have a second image that is just the opposite and looks backfocused. They were taken back to back using center point focusing on the6' mark. I choose to use the front focused image here.
Results:
We have a great illustration of the perspective difference betweena 50mm @ 3'[.91m]and 100mm @ 6'[1.83] lens.
We also have proof positive that the depth of field does not thin in digital cropping as was the object of this experiment.
If you want to take the time download the 3 images and look at each one in succession noting thetext "New Arctic Ocean" in red next to the Nat Geo Magazine Title. That text appears OOF about the same in all three images. Now look at the number "4" in the 50mm @ 3'[.91m] shot, then the number 3" on the last two. Obviously, as theorized, the number 3" in the cropped 50mm shot appears to be "acceptably sharp". Much more than the 100mm version.
Conclusion: I used a 5D to do this. A 5D MII would yield a 10 megapixel image. This would be comparable (less crop sensor symantics) to the output of a 40D. Focus accuracy is a concern, based on the swing in front-back focus I experienced, So Madison, if you haven't given up on that monkey yet, I suggest when trying this technique, take multiple images, refocusing each time.
I also conclude from this test that I could do the same thing if limited to 3ft by using 25mm @f4, crop 1/2 to increase DOF X4 over 50mm. Or at least twice from what I'm seeing here.
That's my take, so for now I'll shut up.
Anybody want a peanut?
LOL [
Chuck
You'd like to think that, wouldn't you? You've bested my sense of humor, which means you must have studied, and in studying you must have learned that DOF is subjective, so you would have put the focus point as far from yourself as possible, so I can clearly not choose the test image in front of me. But, you've also bested my forum post, which means you're exceptionally strong, so you could've put the front-focused shot in your own test image, trusting on your strength to save you, so I can clearly not choose the test image in front of you.
Seriously: I was wrong, and your tests prove it. Backing up and cropping does indeed result in deeper DOF. Furthermore, it shows that digital zoom has deeper DOF than optical zoom. Thank you for your effort. I will try to verify your experiment when I have time.
your shutter speed is far too low for a hand held image, and your minimum focus distance my be pushing it on that camera.
Finally, you may not have enough light for accurate focusing, but certainly your shutter speed is way to low for 58mm it needs to be at least 1/focal length for hand holding with a full frame and 1/focal length x 1.6 for crops. I recommend always getting even higher if possible.
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