Hyperfocal distances
Posted 23/01/2011 - 21:14
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Great so for my 1000-4000mm telescope that works out at 3.125km at the wide end (which is f16) to 12.5km zoomed in (f64) no wonder focusing it has been a pain!
Can you explain how the calculated hyperfocal distance of 4900mm (4.9m) has you setting the focus to 2.5m ?
Can you explain how the calculated hyperfocal distance of 4900mm (4.9m) has you setting the focus to 2.5m ?
Mike
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Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.
.[size=11:].Flickr• WPF• Panoramio
.
Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.
.[size=11:].Flickr• WPF• Panoramio
Posted 23/01/2011 - 21:42
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sorry, yes, you're correct. Set the focus to 5m and everything from 2.5meters on will be in focus.
My example was crappy. I'll post up some video on Vimeo when I get hold of an account and show what I've used this for on the 7D.
Bret
My example was crappy. I'll post up some video on Vimeo when I get hold of an account and show what I've used this for on the 7D.
Bret
my pics: link
my kit: K3, K5, K-01, DA 18-55, D-FA50 macro, Siggy 30/1.4, 100-300/f4, 70-200/2.8, Samsung 12-24/f4, Tamron 17-50, and lots of other bits.
my kit: K3, K5, K-01, DA 18-55, D-FA50 macro, Siggy 30/1.4, 100-300/f4, 70-200/2.8, Samsung 12-24/f4, Tamron 17-50, and lots of other bits.
Posted 23/01/2011 - 21:49
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Here's an online Depth of Field calculator http://www.dofmaster.com/dofjs.html
And here's one which I have on my android phone http://www.appbrain.com/app/depth-of-field-calculator/cn.kamakama.android.dof
And here's one which I have on my android phone http://www.appbrain.com/app/depth-of-field-calculator/cn.kamakama.android.dof
Posted 23/01/2011 - 21:54
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I downloaded the windows version of the DOFMaster calc. Very good
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Posted 23/01/2011 - 23:36
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I like Photobuddy on the iPhone, it contains a bunch of photography info, some parts are a bit unnecessary, but there are features I find useful including the DOF calculator, sunset/sunrise calculator, and the moon phase tables.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!
Posted 24/01/2011 - 18:04
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I read some interesting advice in a copy of "The Asahi Pentax Way" of a vaguely related nature. They advocated that if shooting a landscape you set the lens with the infinity position aligned with the DOF mark for the aperture you're using, as opposed to just setting the lens to infinity. The rationale was that doing this means you're in focus from infinity to a much closer distance.
Most wider angle Pentax lenses (28mm and the Super Takumar 35mm) have orange numbers. Line these up and it becomes a panfocal lens where everything is in focus from infinity to a closer distance.
Most wider angle Pentax lenses (28mm and the Super Takumar 35mm) have orange numbers. Line these up and it becomes a panfocal lens where everything is in focus from infinity to a closer distance.
Matt
Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
Posted 24/01/2011 - 18:26
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Dangermouse wrote:
Most wider angle Pentax lenses (28mm and the Super Takumar 35mm) have orange numbers. Line these up and it becomes a panfocal lens where everything is in focus from infinity to a closer distance.
That's what I do. Or John's method where you just focus a third of the way in to the scene, select a small aperture, and hope for the best!Most wider angle Pentax lenses (28mm and the Super Takumar 35mm) have orange numbers. Line these up and it becomes a panfocal lens where everything is in focus from infinity to a closer distance.
But what if Pentax provided the following facility - focus on the nearest point that you want in focus, then on the furthest. The camera then automatically adjusts the aperture and focus point to ensure both points are in focus. I believe this system has been implemented on some Canon SLR's...
You could even have the camera analyse the scene using the different AF points on a half-press of the shutter, and then come up with an optimal focus/DOF setting.
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1470 posts
17 years
Work: Helsinki; Home: Lahti
focal squared / f x 0.02
that's it. It's not complex.
Example: 28mm lens, f8.
28 x 28 = 784
8 x 0.02 = 0.16
784 / 0.16 = 4900
Therefore: set focus to 2.5m and f8 on that 28mm SMC-M and leave it.
I've been working with this at work for video footage and it works pretty well. Everything really is reasonably in focus, too, and that to infinity.
To make it really easy and to give some reference points, here a quick excel table, working in mm at both f8 and f16. You can do the rest of the maths yourselves
Set focus to these distances and everything from within half of the distance to infinity will be acceptably in focus.
mm....f...distance
10....8....625
12....8....900
14....8....1225
15....8....1406.25
16....8....1600
18....8....2025
20....8....2500
24....8....3600
28....8....4900
30....8....5625
40....8....10000
10....16....312.5
12....16....450
14....16....612.5
15....16....703.13
16....16....800
18....16....1012.5
20....16....1250
24....16....1800
28....16....2450
30....16....2812.5
40....16....5000
hth.
Bret
my kit: K3, K5, K-01, DA 18-55, D-FA50 macro, Siggy 30/1.4, 100-300/f4, 70-200/2.8, Samsung 12-24/f4, Tamron 17-50, and lots of other bits.