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07-16-2010, 12:14 PM   #1
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better lens will produce better low light video on k-x??

if i want to get some better low light footage would a better lens help?

what do you recommend?

07-16-2010, 01:05 PM   #2
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Yes, the larger aperture would help- the 50mm F1.4 would likely be a good start.

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07-16-2010, 03:10 PM   #3
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All cameras (K-x, K-7) will benefit from a good quality, large aperture lens in low-light conditions. Both for still and video.
07-17-2010, 08:04 AM   #4
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im interested in the 50mm F1.4 if anyone has one for sale

07-17-2010, 09:47 AM   #5
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Off course you will take profit from better glass. Your movie will allsoo change because of a different DOF.

I shot this with my K-7 and the FA*85mm/f1.4 set at f2.0
[YT]http://www.youtube.com/watch?v=AW9LYeeZaP8[/YT]
07-17-2010, 11:47 AM   #6
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QuoteOriginally posted by TheoSixx Quote
Ron wrote:
>> Your movie will allsoo change because of a different DOF. <<

Depth of Field (DOF) refers to the range of distance for acceptable sharpness of subject matter in a given framework.
Larger apertures lend themselves to a narrow depth of focus sharpness, where smaller apertures produce better focus (sharpness) over a greater distance.

[at least; that's the way I read the definition.]

Changing the focal length of a lens may not produce a change in DOF, but the aperture will.



Understanding Depth of Field in Photography
A long lens at a given aperture will have a shallower DOF that a shorter FL lens at the same aperture. DOF Calculator.

Last edited by Parallax; 07-19-2010 at 08:17 AM.
07-17-2010, 12:14 PM   #7
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Shallow DOF lenses on my K-7

[YT]http://www.youtube.com/watch?v=ZU2JEQZYMtI[/YT]

[YT]http://www.youtube.com/watch?v=GuCXXi94sNQ[/YT]

[YT]http://www.youtube.com/watch?v=_kvKntLMbIw&feature=related[/YT]

[YT]http://www.youtube.com/watch?v=N8n7YU2uNw0[/YT]

[YT]http://www.youtube.com/watch?v=UJcI2uDOMCc[/YT]

[YT]http://www.youtube.com/watch?v=pVB67azxBZg[/YT]

[YT]http://www.youtube.com/watch?v=E9oN2o5FCik[/YT]

[YT]http://www.youtube.com/watch?v=5KqMWX4vuwU[/YT]

[YT]http://www.youtube.com/watch?v=l4L_ZKCA3DI[/YT]

[YT]http://www.youtube.com/watch?v=KtGtUkf33Hg[/YT]

[YT]http://www.youtube.com/watch?v=FqlnRDq9kDI[/YT]
07-17-2010, 01:49 PM   #8
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QuoteOriginally posted by TheoSixx Quote
Ron wrote:
>> Your movie will allsoo change because of a different DOF. <<

Depth of Field (DOF) refers to the range of distance for acceptable sharpness of subject matter in a given framework.
Larger apertures lend themselves to a narrow depth of focus sharpness, where smaller apertures produce better focus (sharpness) over a greater distance.
Well I was referring to changing the apperture. If you use a 85mm lens (zoom or prime) at f4.0 you have a bigger DOF then using a 85mm lens at F2.0 You're K-7 can when taken a movie at the same scene correct with changing the iso-setting (we can't control) but at the cost of movie quality. That was what I was mening.

Also one lens is not the same in quality as the other is, however in my opinion it is not that critical as in taking stills.

07-17-2010, 03:10 PM   #9
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It does not have to be a better lens.
You can pick an older 50mm 1:1.4 for 30$.
An older 28mm 1:2.8 will already bring better results than your kitlens.


This video was shot using a Pentax k-x with an old manual 50mm 1.4 lens.
Lens description is smc Pentax-M 1:1.4 50mm Asahi opt. co Japan
I set the dial to P
selected ISO 400
pointed the camera towards light and locked the exposure at 1/25 frames per second
Then flipped the switch from P to camera mode. Without pushing the AE-L button again started to film.

The white balance was set to Muted
Saturation 0
Hue 0
High Low key -3
contrast -4
Sharpness 0
07-18-2010, 07:34 AM   #10
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QuoteOriginally posted by jupzchris Quote
if i want to get some better low light footage would a better lens help?

what do you recommend?
A fast lens helps a lot. And fully open, the lenses do still provide tack-sharp renderings because of the relatively low video resolution.

However, a long focal length easily causes shake motion blur and defocussed images because of the shallow depth of filed and the lack of AF in video mode.

Therefore, a 50/1.4 lens isn't the best recommendation.

I'd rather recommend FA*31/1.8, Sigma 30/1.4, FA*24/2, DA14/2.8 or DA*16-50/2.8 at 16mm.
07-20-2010, 11:24 AM   #11
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For head/shoulder shots a 50mm would be ideal with the camera's crop factor. You don't want the camera in the actor's faces. Use a tripod always for those non-dynamic scenes. Your video will compress with better quality when everything in the whole scene is not changing due to camera motion.

Last edited by tuco; 07-20-2010 at 11:30 AM.
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