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"Lens Turbo" to compete with Speed Booster
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PostPosted: Mon May 20, 2013 8:51 pm    Post subject: Reply with quote
Quite interesting discussion on dpreview: http://www.dpreview.com/forums/thread/3486063
To cut to the chase, OP's conclusions.

Quote:
Pros:

- almost 1 stop gain is real, except for cases when a lens has a heavy vignetting
- a slight increase in central resolution. I didn't notice any increase with very sharp lenses, but some increase in soft ones when fully open
- you get (almost) FOV of the FF lenses back, no need to do multiplication, wide angle is back
- it's shorter than a dumb adapter
- it provides a good seal and protection from dust

Cons:

- the biggest problem so far is the softening of the corners. Many FF lenses are soft in the corners already, and focal reducer makes it even worse than on FF camera. Some FF lenses that worked great with a crop sensor showed very noticeable corner softening. In real life shooting, it may or may not be an issue. I noticed most affected lenses are on the short end: 24-28mm. So I wouldn't recommend focal reducer for wide landscape shots, chances are the corners will be visibly soft. The longer lenses behave better and in real life shooting the corners are OOF anyway, so you wouldn't notice it.
- the blue spot caused by the reflections in the adapter, which mostly affects smaller apertures and longer FLs. After a week of shooting I've found only a handful of pictures that had to a various degree visible blue spot in the center.
- increased vignetting: I've only seen strong vignetting on 24mm lenses when fully open. The vignetting goes away at longer FLs and smaller apertures. I took hundreds of pictures by now and I don't think it's a big problem with the lenses I have.
- the gain in speed might be smaller than you think it is. Many zooms have variable aperture. For example, when you take a picture at 24mm without a focal reducer, the lens can be f/3.5, but when you take the same picture with the same zoom with the same FOV at 33mm the lens can be f/4. So you get 1.48x increase in speed, not the 2x you might expect.
- focal reducer is heavier than a dumb adapter.
- two adapters I tried had very tight mount on the lens side, I'm afraid if I leave adapter on a lens for a prolonged time it can bind and will be difficult to remove.


Another review:
http://gtbarnes.com/2013/05/16/nex-lens-turbo-speed-booster-initial-impressions-samples/
Big_is has FD and some other versions for $190 on ebay.

Last edited by fermy on Mon May 20, 2013 10:23 pm; edited 2 times in total


PostPosted: Mon May 20, 2013 9:56 pm    Post subject: Reply with quote
Very useful conclusions fermy.
From a pragmatic point of view I understand from your post that:
- it is of limited use in landscape photography, particularly with wide lenses.
- very useful in portrait, street photography, close-up or whenever a normal or medium tele-lens is needed, especially in low light.
- useful with old normal and short tele-lenses as it may slightly increase the resolution.

Have you tested it with lenses in 135-150 mm range? How it behaves with them?
Theoretically they will become ~95-105 mm with a 2x increase in speed and focusing closer - nice as long portrait and close-up lenses.


PostPosted: Mon May 20, 2013 10:22 pm    Post subject: Reply with quote
The conclusions are not mine, they are from OP in the dpreview thread. I literally copied the text from dpreview, so "I" that you see in conclusions does not refer to me. I'll edit my previous post to make it clearer.

The way I read those conclusions, the gadget is not useless the way glass mount adapters are, but it does not transform your NEX into FF for free, there are penalties. The landscape on gtbarnes.com looks actually decent, so perhaps corner degradation is just a lens weakness, I didn't read the dpreview thread very carefully.

Personally, I am kind of on the fence if I really need that FF look so much, it's tempting to use my FD 24 f2 without crop factor, but other than that I tend to favor normal to tele range. So I would rather wait for further reviews and for the prices to come down a bit more.


PostPosted: Mon May 20, 2013 10:26 pm    Post subject: Reply with quote
Looks like a very useful accessory for many situations.
A pity they can't be made for DSLR bodies.


PostPosted: Mon May 20, 2013 11:09 pm    Post subject: Reply with quote
I still really want one of these for underground. It's can't give any worse IQ when using it with a 24mm than the cheap nasty 0.45 WA screw-on I currently use.

I'll wait until someone from here has a look-see at it, it's not exactly pocket change to throw around.


PostPosted: Mon May 20, 2013 11:53 pm    Post subject: Reply with quote
NewStuff wrote:
I still really want one of these for underground. It's can't give any worse IQ when using it with a 24mm than the cheap nasty 0.45 WA screw-on I currently use.

I'll wait until someone from here has a look-see at it, it's not exactly pocket change to throw around.

I will buy one as soon as an Minolta MD or better Sony AF occurs on Ebay


PostPosted: Tue May 21, 2013 12:07 am    Post subject: Reply with quote
MD is already on ebay, same $190. Click here to see on Ebay


PostPosted: Tue May 21, 2013 1:24 am    Post subject: Reply with quote
I found this:

http://www.ebay.com/sch/m.html?_odkw=&rd=1&item=171043930481&_osacat=0&_ssn=big_is&_trksid=p2046732.m570.l1313.TR0.TRC0&_nkw=speed+booster&_sacat=0&_from=R40


PostPosted: Tue May 21, 2013 1:57 am    Post subject: Reply with quote
the_x_vision wrote:
I found this:

http://www.ebay.com/sch/m.html?_odkw=&rd=1&item=171043930481&_osacat=0&_ssn=big_is&_trksid=p2046732.m570.l1313.TR0.TRC0&_nkw=speed+booster&_sacat=0&_from=R40

$190 is a fair price consider consider the retail price is about $150 in China.


PostPosted: Sun May 26, 2013 6:42 pm    Post subject: Reply with quote
anybody knows wheter there is a Konica AR or Olympus OM Lens Turbo in the makes? Didn´t get a replay...


PostPosted: Mon May 27, 2013 9:17 am    Post subject: Reply with quote
now I have answers:

Metabones: "We will consider to develop a konica adapter at next half-year…"
didn´t ask about OM

Mitakon :"We do not plan to do it.
Thank you so much."
concerning Konica/OM


PostPosted: Mon May 27, 2013 2:04 pm    Post subject: Reply with quote
robau wrote:
now I have answers:

Metabones: "We will consider to develop a konica adapter at next half-year…"
didn´t ask about OM

Mitakon :"We do not plan to do it.
Thank you so much."
concerning Konica/OM


The lens turbo I want should be for Pentax K, M42 and possibly Olympus OM lenses. I'll get the Pentax K lens turbo, stack the M42>K adapter for the M42 and convert the mount of the Zuikos I want to use with the lens turbo to Pentax K which is easy and will be fun to do: http://forum.manualfocus.org/viewtopic.php?id=8570

as it looks the mount on the lens turbo is easily removable, if one wanted to have a lens turbo for Zuikos only I imagine that changing the mount on the lens turbo from Pentax K to OM should be very easy.
however i expect that it won't take long before a OM lens turbo will be available


PostPosted: Mon May 27, 2013 2:40 pm    Post subject: Reply with quote
Roxsen and big_is have them for £125. I'm saving up for an MD one.

They have Pentax K, Nikon Ai, Canon FD and Minolta MD


PostPosted: Thu Nov 07, 2013 5:33 pm    Post subject: Reply with quote
I just like to add that I have ordered my LensTurbo directly from "MXcamera", because the only EBAY seller that offered the one I needed was a seller that I had some bad experiences with before!

MXcamera was great! Very pleasant communication and excellent service.
Although their online shop did not work properly, I was able to order everything via direct and personal EMail communication.

They were always willing to help and inform me even when I had problems with the German shipping company (DHL Express)!

Last edited by LucisPictor on Fri Nov 08, 2013 11:17 am; edited 1 time in total


PostPosted: Thu Nov 07, 2013 6:57 pm    Post subject: Reply with quote
I got a PK lens turbo as birthday present. During the last weeks I have used it with several lenses, not all of them performed well.
Some suffer from heavy field curvature (as told by many others).
I reallly enjoy using the LT for low light portrait works with nearly all lenses but the following perform best:

Leitz Summicron-R 2/90 (leitaxed) - delivers a great Bokeh
Leitz Elmarit-R 2.8/135 (leitaxed) - sharper than without LT! focused to infinity it is sharp until the corners @ F5,6
SMC Pentax M 1,4/50 - performs really well, field curvature seems be be less pronunced than on Pentax 1,7/50 and Leitz 2/50

Those three are of "longer" focal length, all of them get very sharp across the entire frame stopped down and all of them got a big last lens element. Is it possible that the diameter of the last element of the lens is a critical factor for low field curvature with the LT or ist it just random rubbish connceived by me?

Timo


PostPosted: Thu Nov 07, 2013 9:17 pm    Post subject: Reply with quote
kuuan wrote:

however i expect that it won't take long before a OM lens turbo will be available


Or not, with the sony a7 / a7R coming in.


PostPosted: Fri Nov 08, 2013 1:02 pm    Post subject: Reply with quote
robau wrote:
anybody knows wheter there is a Konica AR or Olympus OM Lens Turbo in the makes? Didn´t get a replay...

Been waiting a long time but the wait is over now, got a a7 Smile
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