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Zhongyi Lens Turbo II and GH5


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The camera does not care whether it's a zoom or not....so if you're shooting at say 24mm on the Sigma, you calculate at 24 plus crop change on the booster and set that...if you Google this info, there is a DVXUser thread that explains the GH5 used in conjunction with a zoom and booster....but in a nutshell, you do not calculate the M4/3 crop....a 35mm lens is always a 35mm lens....if however you add a speedbooster at say a .64 crop, it changes the FOV of the lens...if you're using your zoom at 35 mm you'll set the focal length for IBIS at 22.4 with a .64 crop booster...35 x .64 = 22.4mm

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19 minutes ago, Fritz Pierre said:

The camera does not care whether it's a zoom or not....so if you're shooting at say 24mm on the Sigma, you calculate at 24 plus crop change on the booster and set that...if you Google this info, there is a DVXUser thread that explains the GH5 used in conjunction with a zoom and booster....but in a nutshell, you do not calculate the M4/3 crop....a 35mm lens is always a 35mm lens....if however you add a speedbooster at say a .64 crop, it changes the FOV of the lens...if you're using your zoom at 35 mm you'll set the focal length for IBIS at 22.4 with a .64 crop booster...35 x .64 = 22.4mm

Thanks...ideally though i dont want to have to go in and change this focal setting everytime i choose to zoom in or out?..is there not an optimal setting or range to suite any focal range on the lens?

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I would imagine averaging the zoom range out and setting it at that...on longer zooms....say a 25 to 200, this is bound to cause more problems than say a 18-35...My advice would be test it....if you zoom during the shot (I don't, but opt for a doll/slider instead) you won't have a choice anyway...the better alternative in that case would probably be to shoot on sticks...still, only you know how you'll use the camera...I would test all your potential scenarios.

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On 14.11.2017 at 3:01 PM, funkyou86 said:

You mean the stabilisation settings? Yes, only native lenses communicate with the body (or maybe the metabones as well, not sure). It's not a big deal for me, the camera remembers your previous setting, so next time you turn it on, it just asks if the settings are still right.

How dp you change your apperure on Sigma 18-35? Is it EF or Nikon mount? I thouth Lens Turbo doesnt have electronic contacts, so its only some manual way to change apperture.

On a Nikon speedbooster, there is ring for change it, but what about Lens Turbo?

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8 hours ago, srgkonev said:

How dp you change your apperure on Sigma 18-35? Is it EF or Nikon mount? I thouth Lens Turbo doesnt have electronic contacts, so its only some manual way to change apperture.

On a Nikon speedbooster, there is ring for change it, but what about Lens Turbo?

I own a Canon 600D as well :) so if needed, the aperture is set on that camera. But once you have the sigma 18-35 in your collection you'll find yourself always shooting open wide.

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Ok received the Zhongyi lens turbo yesterday along with a normal nikon to m43 dumb adapter to use with the nikon sigma 18-35 with the GH5.

First impressions - No issues I can see at all with Vignetting and if it is there it is not noticeable, at the wide end with the Zhongyi which is around 13mm after conversion and it seems fine.

In terms of image quality I am finding it hard to see any noticeable difference between the image out of the Sigma through the dumb adapter or the Zhongyi which is great news to me. I shot some stuff in doors and saw comparable quality in terms of sharpness and resolution throughout. The zhongyi might be more prone to flaring when pointed at a light source but that is avoidable..

In terms of the IBIS and focal settings you have to input every time you turn the camera on. I think you pretty much have to stick to the focal length setting that relates to the focal length that you are going to use on the lens. So if you set it at 18mm, shoot at 18mm and you will get good stabilisation. if you set it at 18mm and then zoom in at 35 you get strange warping effects and issues. there is a delay from when panning to when the sensor \stabilisation recognises the pan and then catches up. if i set the focal length in cam to 35 and shoot at 35 again this looks great and stable, but if i then choose to go to 18mm i get the same issue, strange warping effects and delayed panning.

The issue is the focal length setting in camera can only be changed when you are not recording. this means you cannot while filming both change your lens focal length and the in camera focal length setting. You basically have to choose what focal length you will be shooting at before you start recording and stick to it unless you want some adverse effects....

If you had to stick with one setting I would say you get better results going with the widest setting, so for the sigma you can set it to 18 and get great results at 18 and then the performance gets worse the more you zoom in. I think this option is better than setting the focal length to 35 which then only gives you great results at the far end, and then degradation the more and more you zoom out.

all in all in terms of the Zhongyi...I would not hesitate to recommend it as a very cheap alternative to the speed booster.

 

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48 minutes ago, lmackreath said:

In terms of the IBIS and focal settings you have to input every time you turn the camera on. I think you pretty much have to stick to the focal length setting that relates to the focal length that you are going to use on the lens. So if you set it at 18mm, shoot at 18mm and you will get good stabilisation. if you set it at 18mm and then zoom in at 35 you get strange warping effects and issues. there is a delay from when panning to when the sensor \stabilisation recognises the pan and then catches up. if i set the focal length in cam to 35 and shoot at 35 again this looks great and stable, but if i then choose to go to 18mm i get the same issue, strange warping effects and delayed panning.

So in order to do change it every time we should turn the camera off and on again?

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21 minutes ago, Samin said:

So in order to do change it every time we should turn the camera off and on again?

No its not that extreme. If you want to change it you can go into the stabilser options in the menu and the focal length settings are in their. The annoying thing is that even if you choose not to change the focal setting the camera will ask you to confirm the setting each time you turn it on..a possible future firmware update would be great to remove this..

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On 11/23/2017 at 1:41 AM, lmackreath said:

Ok received the Zhongyi lens turbo yesterday along with a normal nikon to m43 dumb adapter to use with the nikon sigma 18-35 with the GH5.

First impressions - No issues I can see at all with Vignetting and if it is there it is not noticeable, at the wide end with the Zhongyi which is around 13mm after conversion and it seems fine.

 

I'm curious if you are using a cropped mode on the GH5, because a quick test shows you get severe vignetting with the Lens Turbo II on full-sized m43 format when paired with the Sigma 18-35 at shorter focal length settings.  This despite the fact that the Lens Turbo II has less reduction (0.726) than the Speed Booster (0.71)

5a1f0a88d9261_SBUltravsLTIIonGH4withSigma18-35s.thumb.jpg.5ae20122fc8c28dac6f63f1e12206413.jpg

On 11/13/2017 at 1:45 AM, anonim said:

Slightly bigger crop factor of Zhongyi II is your friend :) It has crop factor lowering to 0.726 so you are pretty inside safe margin even with 18-35.

Personally I used Zhongyi with GH2 witch has multiaspect ratio crop smaller than GH5 - of 1.86 - and there was no problem with full frame lenses, so you should no worry at all with Sigma Art full frame lenses.

BTW I found that Zhongyi has very little bit sharper reproduction than first version of Metabones speedboosters.

Even though the 18-35 has sufficient image circle diameter at 18mm to handle 0.71x focal reduction, the lesser 0.726x factor of the Lens Turbo II does not mean you are "inside safe margin".  The issue here is that image circle diameter is only part of the story.  Equally important is the exit pupil distance of the lens, and how well the focal reducer handles longer exit pupil distances.  This is where the Lens Turbo II completely falls apart, because the 18-35 is nearly telecentric at the wide end, with an exit pupil distance of 150mm.  My simple test above shows what happens:  the vignetting with the Lens Turbo II is clearly caused by the focal reducer, and not the Sigma 18-35.

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