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05-26-2014, 12:34 AM - 4 Likes   #1
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Lens Turbo II PK-NEX First Impression

Pentax lens compatibility tested on Lens Turbo II so far by forum members. Thank you jcdoss and Tessar.

Working
Pentax F 17-28mm F/3.5-4.5
Pentax K 24mm F/2.8
Pentax FA 20-35mm F/4
Pentax M 40mm F/2.8 Pancake by Tessar.
Pentax FA 43mm F/1.9
Pentax M 50mm F/1.7 by Tessar.
Ricoh 55mm F/1.2
Pentax FA 77mm F/1.8
Pentax FA 85mm F/1.4
Pentax F 70-210mm F/4-5.6

Not Working fully but resolved by using shimming
Pentax M 20mm F/4 by jcdoss
Pentax M 28mm F/3.5 by jcdoss

Please refer to jcdoss's post for more details on shimming

Not Working fully
Pentax FA 31mm F/1.8
Pentax M 35mm F/2.8 by Tessar.
Pentax M 28mm f/2.8 1st version by Tessar.


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Hi all:

I just received Lens Turbo II PK-NEX from Taobao last week and ordered a NEX-6 along with it. I would like to share some thoughts for those who is interested.

The adapter itself is hefty but good quality, somewhere between Kipon and Voigtlander. When mounted on NEX-6, it is very stable. The weight itself is 175g plus 345g of NEX-6. Total weight is 520g. Not exactly light but not much weight saving compared to K-30/K-50 given K-30/K-50 has good viewfinder and AF.

Nevertheless, the balance is good and focal length and aperture is multipled by around 0.72X ( MAX aperture is limited to F1.0 no matter how bright original lens is). The DOF is thin with Lens Turbo II and focus peaking doesn't always work but EVF with 10X magnification helps a lot. Under bright sun, GXR b/w mode or K-3 optical viewfinder is definitely better. But overall, for the price, I am happy with the purchase.

Since this week's is starting of raining reason accompanied by busy schedule, I was only able to take few snapshots using three lenses:

K 24mm F/2.8
FA 20-35mm F/4
Ricoh 55mm F/1.2

NEX-6 setting is standard, +1,+1,+1, +0.3EV, AWB, SOOC fine JPEG and resized to 1MP using lightroom(standard sharpen for screen) without any additional tweaking. Uncropped as I think people will be interested in corner performance. I will post more samples with other lens like FA limiteds in the next few weeks.

____________________________________________________________________________________________________________________________________________________________________________________________________________________________

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Last edited by chaosteo; 07-23-2014 at 04:52 AM.
05-26-2014, 01:38 AM   #2
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Thank you for this post. I am very interested in the Lens Turbo II.

It's hard to judge all of it's optical qualities from these images, but it doesn't seem too bad. Flare seems well controlled, which is good to see.

I'll certainly be keeping a watch on this thread for any further image samples. I'd be particularly interested to see how it goes when shot in low light. I always worry about ghosting under low light when using filters, and in a sense a Lens Turbo is kind of a big filter.
05-30-2014, 11:18 AM - 2 Likes   #3
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Pentax 43mm Limited Quick Follow-up:

I have a chance to test 43mm limited (MIJ first 15000 batch) during my business trip today. It is kinda of cloudy today and NEX-6 creative style is set to Standard with -2, +1, +0, with +0.7EV as I found previous setting too contrasty, yet new setting output turns out kinda of lack of punch. However, I will still post originial SOOC JPEG here as I didn't shoot RAW. (P.S. This follow-up should not be compared directly to initial post)

In most settings, Lens Turbo II performed not bad, but seems to lack a bit of oily, creamy, and stardust compared to shooting it directly on K-3. #3,4,5 are shot through bullet train window (u can treat as attaching one giant bad quality filter).

For rawr, I did LED lamp test as I would say it mostly would most represent one of most difficult light source, even compared to industrial direct spotlight used at public setting. My LED lamp is at its max output at 427lm with color rendering index of 85. K-3 and NEX-6 both shot under M mode using ISO 200, 1/200 shutter and F4.5, I would say K-3 sample(#9) perform much better with much less flare or ghosting compared to Nex-6 with Lens Turbo II(#10).
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05-30-2014, 01:05 PM   #4
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I like the capture of the engagement photo shoot?

05-30-2014, 04:12 PM   #5
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QuoteOriginally posted by chaosteo Quote
For rawr, I did LED lamp test
Thank you very much for performing this test. The testing scenario was harsh, but optical problems seem well controlled.

If this is the worst it gets with direct, harsh LED lighting, in normal low-light use (with perhaps more indirect light sources) any flare and ghosting would likely not be apparent. Very encouraging test results.
06-03-2014, 05:17 AM   #6
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I have the original lens turbo for my K mounts on an NEX. I get overall pretty good results, but sometimes the glare or reflection can ruin a shot if at just the right angle. Other times I am blown away by what it helps achieve. I definitely want to try the new model as the original hasn't left the body in months and an improved model would live on my mount. Poor man's full frame and I can live with that for the time being.

Jason
06-08-2014, 09:00 AM   #7
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ALERT

For those who is interested in getting lens turbo II, I am not sure whether this is a problem with first generation. But my lens turbo II is not working well with 31mm limited !!!

The lens focus hit an end at focusing distance between 1 to 2 meter. Per 31mm design, the back glass module of the lens moved further passing the lens mount to a degree that focusing pass 2 meter was not possible as it would hit the glass element of lens turbo II. My 31mm is fully functional on K-3, no problem focus till infinity on K-3 and K10D. Also, the lens itself was recently serviced by Pentax Japan in Feburary this year.

I tried all my remaining wide angle lenses: F 17-28mm, FA 20-35mm, K 24mm. They don't exhibit this problem. This is sad given 31mm is my favorite lens. Too late for me to return both NEX-6 and lens turbo II now. Maybe A7 is a better solution afterall before Pentax comes up with full frame. I also wrote an email to Zhongyi and let's see how they respond. Just wanna you all know in advance.

Thank you

Last edited by chaosteo; 06-08-2014 at 06:44 PM.
06-10-2014, 04:49 PM - 1 Like   #8
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Infinity adjustment for Lens Turbo.

Hello,

I hope I'm not too late to help you. I own a Metabones Speedbooster (for Canon FD), so infinity adjustment is quite easy for me :

Metabones® Infinity adjustment

I guess that does not help you out too much, because a Lens Turbo don't have such screw (the old one, I haven't read anything about the mk2 yet). But I came across this page a long time ago and hope this trick do the Job for you:

https://www.flickr.com/photos/kodomut/9218550661/

Let us know, if that helps.

Best, No Maam.

06-12-2014, 02:22 AM   #9
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Hi No Naam:

Thank you for the suggestion.

However, I looked at the flickr page and decided not to try it for now.

1. Still waiting for manufacturer’s email since I haven't received anything from them after I emailed them on Sunday. I don't want to void my warranty now if there is any...

2. After looking at the flickr page, I examined closely my adapter and 31mm. It was not focusing beyond 2m due to the rear optical element moving pass through the inside of lens mount too much to cause the rear optical element making contact with the optical element of the lens turbo ii. If you look at 31mm, the rear element just keeps protruding when you focus toward infinity. If I were to remove the lens adapter ring like the flickr indicates, it should just make the situation worse given that 31mm would bite the lens turbo ii deeper and there would be less room in between lens rear optical rear element and the lens turbo ii optical element. I really wish lens turbo ii having a solution like speed booster despite I am uncertain either solution will allow the focal reducer to maintain the same optical performance after infinity adjustment.

3. Well...31mm is a $ lens and quite a fragile one in mechnical design compared to 43mm and 77mm. Besides initial acquisition cost, I also paid quite an amount for my repair and maintenance in February. I guess I am not risking it for now.

Last edited by chaosteo; 06-12-2014 at 03:16 AM.
06-12-2014, 04:14 AM   #10
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What s the lens turbo meant to do? I seems to produce relatively low contrast images.


Your pictures make me homesick for a place I have not been for a couple of years. Which THSR station were you at?


I really like the walls with red bricks and barbed wire. They bring back so many happy memories from various dates from 1985 onwards.
06-13-2014, 02:33 AM   #11
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QuoteOriginally posted by tim60 Quote
What s the lens turbo meant to do? I seems to produce relatively low contrast images.
1. It acts opposite of teleconverter. It reduces ur focal lens by multiplying it by 0.726x and when you adapt on apsc body, it gives u 1.089x equivalent of stated focal length. For example, 50mm becomes 54.45mm.

It has effect on aperture too. It increases ur aperture by multiplying it by 0.726x. For example, F1.4 lens becomes F1.016 and equivalent 35mm depth of field on apsc body is 1.525.

I am still tuning for desirable contrast setting for NEX-6. Its JPEG rendering is different from Pentax.

2. U should visit back sometimes. Tainan changes a lot. First few were from Tainan stations. Last few were from Taichung.

3. Glad u like them. They are old houses from Japanese ruling era. Tainan city does a good job on many historical buildings and culture preservation.


---------- Post added 06-13-14 at 05:34 PM ----------

QuoteOriginally posted by Clicker Quote
I like the capture of the engagement photo shoot?
Thank u

Last edited by chaosteo; 06-13-2014 at 02:54 AM.
06-13-2014, 05:14 AM   #12
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QuoteOriginally posted by tim60 Quote
What s the lens turbo meant to do? I seems to produce relatively low contrast images.
As chaosteo said, a Lens Turbo is the opposite of a TC. It is a lens that goes between an APS-C camera and full frame lens to mimic a true full-frame system. The lens Turbo collects all the light from a full-frame lens and focusses it down to an APS-C image circle. The lens behaves as though it was mounted on a FF camera, i.e. crop factor compensated so that AOV and DOF are FF-equivalent. Because of the light concentration over a smaller surface, you gain a stop of aperture, which compensates for FF cameras improved SNR and shallower DOF.

My FA 35mm f2.0 on a K-3 or a6000 is: (35x1.5)mm, f/(2.0x1.5), = 53mm f/3.0 equivalent.
With a Lens Turbo on my a6000, my FA 35mm will be: (35x1.5x.72)mm, f/(2.0x1.5x.72) = 38mm f/2.2 equivalent.
So it not quite FF equivalent, but close enough that I'm not going to do exact math when I'm wondering which lens to use. I'll just use my Turboed FA 35mm on an a6000 as I would if it were mounted on an A7R.

Of course nothing is free. A FF lens on an APS-C camera has the corners cropped, which are weaker than the center. Aberrations like CA, coma, fringing, will be exacerbated, just as they are with a TC, due to the Turbo glass element not being specifically corrected for the lens it is used with, and yes, there is a slight loss of contrast due to the extra glass. What this means to me is that a Turbo should only be used with superior lenses. I don't use my teleconverters with consumer zooms, I use it with my best primes. I expect a Turbo will be similar but even more demanding.

Maybe I should have gotten a Metabones SpeedBooster. My Pentax 1.4x TC didn't cost $138 like the Turbo did. But then I don't know how much use the Turbo will get, so it made sense to start there.
06-13-2014, 02:17 PM - 1 Like   #13
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QuoteOriginally posted by chaosteo Quote
1. It acts opposite of teleconverter. It reduces ur focal lens by multiplying it by 0.726x and when you adapt on apsc body, it gives u 1.089x equivalent of stated focal length. For example, 50mm becomes 54.45mm.

It has effect on aperture too. It increases ur aperture by multiplying it by 0.726x. For example, F1.4 lens becomes F1.016 and equivalent 35mm depth of field on apsc body is 1.525.

I am still tuning for desirable contrast setting for NEX-6. Its JPEG rendering is different from Pentax.

2. U should visit back sometimes. Tainan changes a lot. First few were from Tainan stations. Last few were from Taichung.

3. Glad u like them. They are old houses from Japanese ruling era. Tainan city does a good job on many historical buildings and culture preservation.


---------- Post added 06-13-14 at 05:34 PM ----------



Thank u


Now I know what confused me about the THSR stations - I have used most of the stations along the line - except ChiaYi and BanChiao. I saw elements from Tainan - the tree with the orange flowers which I have only seen around Tainan and the bus stop, but I never went outside just there so did not seen that view of the architecture. Those walls look like they had not changed since my first trip to Tainan in 1985. I always liked that city.


I liked your view of the place because it conveys atmosphere.
06-13-2014, 06:42 PM - 2 Likes   #14
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A few taken with my Lens Turbo with an FA35 and FA50 on an NEX-5n

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Jason
06-13-2014, 07:02 PM   #15
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Very encouraging results Jason. I can't wait till mine arrives. The FA 35 and FA 50 will definitely be going for a spin.
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