/p/ - Photography » Thread #3440092

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Anonymous Mon 25 Feb 2019 20:07:52 No.3440092 View View Reply Original Report

Have you ever tried combining a speedbooster with a converter?

Rather esoteric, but I want to use my speedbooster with a Pentax-K mount with some old manual olympus lenses. Would I find a dumb converter from Pentax-K to those lenses, could I use them without a problem?

I'm pretty sure it would impact quality in a negative way, but it would be 3 okayish lenses nearly for free.

So, basically MFT to Pentax-K speedbooster and Pentax-K to "Whatever those Olympus lenses have".

Anonymous

Anonymous Mon 25 Feb 2019 20:16:14 No.3440097 Report

Quoted By:

Yeah that's what you have to do to adapt and speedboost an Olympus lens, except I did this with canon adapter

Anonymous

Anonymous Mon 25 Feb 2019 20:21:58 No.3440100 Report

Quoted By: >>3440117

It should not be a problem as long as you can find an adapter where you can still open and close the aperture. At least on my old Pentax K lenses while they're mounted you can twist the aperature ring all you want, it only actually closes when you press the shutter. There should be adapters that let you open and close it freely, but I don't know for sure.

Anonymous

Anonymous Mon 25 Feb 2019 20:24:42 No.3440104 Report

Quoted By: >>3440116 >>3440181 >>3440193

>>3440092
Quality is actually improved. You gain speed and sharpness, the downsides is that speedboosters are clumsy, nerf af and good ones are expensive. And you do need metabones ones to at least keep fringing to a minimum.
https://www.eoshd.com/2013/08/metabones-speed-booster-for-micro-four-thirds-review/

Anonymous

Anonymous Mon 25 Feb 2019 20:51:43 No.3440115 Report

Quoted By:

Thank you so much. I'm pleasently suprised by how polite this board actually is.

I really thought to get bashed for using MTF or for even considering using something else than the most pro and official lenses.

Really, thank you.

Anonymous

Anonymous Mon 25 Feb 2019 20:52:58 No.3440116 Report

Quoted By: >>3440149 >>3440163

>>3440104
As far as I know, I need a Viltrox one, because there are no Pentax-k ones from Metabone.
Or have I actually skipped it?

Anonymous

Anonymous Mon 25 Feb 2019 20:55:21 No.3440117 Report

Quoted By: >>3440119

>>3440100
I have this exact problem with an old portrait lense that would just not manually set aperture.
Got me so frustrated.

Anonymous

Anonymous Mon 25 Feb 2019 20:58:27 No.3440119 Report

Quoted By:

>>3440117
Maybe you can cut off the lever on the lens.

Anonymous

Anonymous Mon 25 Feb 2019 21:35:34 No.3440149 Report

Quoted By:

>>3440116
Ok, there seems to be no Viltrox MTF to Pentax-K adapter...

Do you know which mount has the cheapest or most "bang for the buck" old lenses?

Anonymous

Anonymous Mon 25 Feb 2019 22:24:12 No.3440163 Report

Quoted By: >>3440376

>>3440116
Didn't check, I thought they had it since they have some weird mounts for mft. Vitrox then. Forgot to add, that you'll see improvement only on shorter ranges, up to 50mm, the rest is kinda pointless since that cheap 40-150 olympus kit lens easily outresolves any adapted regime.

Anonymous

Anonymous Mon 25 Feb 2019 23:06:52 No.3440181 Report

Quoted By: >>3440183

>>3440104
That article has so many errors in it it's funny. A 50mm full frame 0.71x speedboosted on MFT won't be equivalent to 35mm f1.0

It's going to be equivalent to 71mm f~1.98 since you have to account for the 2x cropfactor that MFT has as well if you're going to do conversions like those. And even then that F number only tells you about the DoF, the T stop will still be the same. So you gain additional light but it's spread out over a bigger image.

Anonymous

Anonymous Mon 25 Feb 2019 23:13:03 No.3440183 Report

Quoted By: >>3440185

>>3440181
uhm... do you know how speedboosters work? They decrease fov, there is no crop factor to speak of, it's the reverse. Same for apertures.

Anonymous

Anonymous Mon 25 Feb 2019 23:18:51 No.3440185 Report

Quoted By:

>>3440183
Yeah, by converting the Nikon 50mm 1.4 to MFT you get and effective field of view of 100mm and an f number of 2.8 because of the 2x cropfactor of MFT. Then you also add in a speedbooster that has a """crop factor""" of 0.71x. So that effective 100mm f2.8 becomes a 71mm f1.98.

Another way to look at this is that the speedbooster reduces the crop factor of the MFT camera to an APS-C one which is still around 1.5x.

Anonymous

Anonymous Mon 25 Feb 2019 23:45:01 No.3440193 Report

Quoted By: >>3440194

>>3440104
>Quality is actually improved. You gain speed and sharpness.
To clear this. It's improved for the lens used. So 50mm with speedbooster will be sharper than the same 50mm with adapter. Native lenses are sharper.

Anonymous

Anonymous Mon 25 Feb 2019 23:47:15 No.3440194 Report

Quoted By:

>>3440193
Also depends on speedbooster. Some cheap ones will degrade everything. It's another bit of glass, after all.

Anonymous

View Same Google ImgOps iqdb SauceNAO max taste.jpg, 693KiB, 1565x1045

Anonymous Tue 26 Feb 2019 04:24:34 No.3440324 Report

Quoted By:

I've also been playing with a focal reducer and found that adding spacers around it does barely anything except greatly reduce the distance at which I can actually focus.
In theory the distance from focal reducer to image (sensor) plays a part in the equation that determines how much it changes the focal length of a lens in front, but there must be something else going on that compensates for that.
I would guess that if you put adapter in front of focal reducer, it will work as originally intended.

Anonymous

Anonymous Tue 26 Feb 2019 06:38:46 No.3440376 Report

Quoted By: >>3440780

>>3440163
Is this 40 - 150 mtf or full frame?

I get so confused by this...

Anonymous

Anonymous Wed 27 Feb 2019 01:46:30 No.3440780 Report

Quoted By:

>>3440376
MFT. There are two 40-150 lenses by Olympus one by Panasonic.

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