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Subject: Comparison of 3 lenses in digiscoping [Print This Page]
Author: cwchan    Time: 26/04/2010 17:29     Subject: Comparison of 3 lenses in digiscoping

Panasonic pancake 20mm f1.7 (setting at f4.5)
Olympus pancake 25mm f2.8 for 4/3, need adaptor for using on Panasonic G1(setting at f4.5)
Panasonic kit 14-45mm zoom (setting at 23mm f4.8)

All were used on Lumix G1, setting at ISO 100, in raw format, process in Silkypix without any post-adjustment.
A 30X scope is used in the test.

The original cropping

The 20mm


The 14-45mm zoom at 23mm (very serious vignetting at the four sides/corner)


The 25mm


-----------------------------------------------
The following are 100% cropping of above images
The 20mm


The 14-45mm zoom at 23mm


The 25mm


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The auto focus of these three lenses all work fine in my 30X scope.
The 25mm Olympus performs a bit soft when compare with the other two Pansonic lenses, this is not strange due to its longer focal length and my G1 might not be equipped with the appropriate firmware that the lens is not fully compatible with my G1 giving the best optical result.

[ Last edited by cwchan at 26/04/2010 18:39 ]
Author: puppymic    Time: 26/04/2010 17:42

haha！ Good, more testing please
Author: mhs    Time: 27/04/2010 11:09

Thanks cw.
Author: lwingkay    Time: 27/04/2010 14:31

Dear Chak Wing,
Thanks for the comparison. Two side issues which I think you are most capable of giving advice on with your knowledge on digiscoping:
a) Is it inconvenient to digiscope with a prime lens (as opposed to the zoom lens where the focal length can vary) knowing that in such a long focal length environment, the convenience from a zoom lens really helps with framing?
b) It seems a little bit difficult to mount an adaptal on the 20mm lens that you are using. You can mount it directly on the DCA using the screw furrows at the front end of the 20mm lens but I think you will be reluctant to do so as in the long run, irreversible damage will be done to lens. I saw in this forum that you tailor made an adaptor for use on the 20mm. At that time, I had the feeling that it was a little bit flimsy as the adaptor might easily slip off from the lens (I hoped I got this wrong) on prolonged manuvering arising from metering, adjusting exposure and focusing as well as when one carries the digiscoping set around to look for birds. Would like to know whether such are the case and whether improvements have been made to the adaptor thus far?
Regards,
Peter Leung

PS: Probably, the 20mm I mentioned above was the 25mm Panasonic Pan Cake that you commented on last time.

[ Last edited by lwingkay at 27/04/2010 14:37 ]
Author: cwchan    Time: 27/04/2010 19:26

Hi Peter

(a) Prime lens is for those who asking for the best optical sharpness and light weight. For convenience, zoom lens absolutely wins the prime lens in field usage. However, don't forget the long side of the zoom lenses are normally not acceptable in sharpness.
(b)Your are right, the old design is not strong enough in the rough field usage. However, Chan C-fu modified it. The mount is now strong as tank.

CW
Author: lwingkay    Time: 27/04/2010 22:29

Re: The mount is now strong as tank

Interested in knowing what the improvements are. Can you show how you assemble parts together?

Pete
Author: lwingkay    Time: 28/04/2010 10:10

Dear Chak Wing,
You're using Panasonic G1 for digiscoping. Two questions for your expert advice:
1) The first question is about using G1 with Swarvoski's TLS 800.
My intended combo is 80 HD STM + TLS 800 + Nikon conversion mount + 4/3 conversion mount (I don't think there is 4/3 conversion mount for TLS 800) + a camera from the Panasonic's G series.
I take the advantage of the absence of the reflex mirror in the G series.
2) The second: whether there is the manual flexible spot focusing device in the G series?
Such is vital for precisely focusing birds' eyes during shooting.
Thanks in anticipation for your attention to the above.
Regards,
Peter
Author: cwchan    Time: 28/04/2010 12:44

Quote:
Original posted by lwingkay at 28/04/2010 10:10
Dear Chak Wing,
You're using Panasonic G1 for digiscoping. Two questions for your expert advice:
1) The first question is about using G1 with Swarvoski's TLS 800.
My intended combo is 80 HD STM + TLS  ...
Hi Peter,

(1) A very good suggestion, if you intend switching from one system (nikon) to another(the m4/3) from time to time. Alternatively, you can also get the T2-m4/3 mount direct, which can be bought in the market.
(2) Yes, there is a manual focus enlarging spot for your ease focus in G1 and GH1, a very useful function indeed, in particular for this 800mm f10 slow lens . I have no idea if other models also equipped with this device.

CW
Author: lwingkay    Time: 28/04/2010 16:09

Re: you can also get the T2-m4/3 mount direct, which can be bought in the market.

I should have asked the following in my first posting on this.
a) whether there is a mount for linking the TLS 800 with G1 direct?
You mentioned the T2-M4/3 mount. Does it mean that you have to mount the 4/3 mount on the T2 when using the TLS 800. Or, does it simply mean that there is a 4/3 mount that can be directly mounted on the TLS 800.
Also, where can you buy that mount?
b) Is automatic metering still possible on the G1?
In Nikon, we configurate the lens setting to f10 using the Non-CPU function button in the camera body. Is it the same for G1?
I have been thinking that metering is done by measuring reflected light from the sensor surface right at the moment of exposure, i.e. TTL-off-the-sensor metering SIMILAR TO the one used in the OM bodies (TTL-off-the-film) of the SLR era. If that is the case, then no configuration is required.
c) It is nice that G1 can enlarge a section in the view finder for detailed focusing.
But then in G1, can I move the focusing spot to locations where I want to focus? This function is provided in Nikon 8400.
Thanks for your patience in replying.
Peter

[ Last edited by lwingkay at 28/04/2010 16:56 ]
Author: cwchan    Time: 28/04/2010 17:11

Quote:
Original posted by lwingkay at 28/04/2010 16:09
Re: you can also get the T2-m4/3 mount direct, which can be bought in the market.

I should have asked the following in my first posting on this.
a) whether there is a mount for linking the TLS 800 wi ...
(a) There is one single mount (T2-m4/3) with its one end (the screw side) fitting to the scope and the other end to G-1 body. Try the shops at Apliu Street.

(b)Automatic metering is possible, and very accurate too, in the G1. Just setting the DC in A-mode(Aperture priority), the DC does the rest, no need to doing anything.

(b) You can move the spot manually to the location  which you want to enlarge for precise focusing. Very useful.



Author: lwingkay    Time: 29/04/2010 00:07

Thanks for replying sooooooo quickly. I did visit some shops in Mong Kok to check things out. The exposure is pretty okay and both the EVF and LCD are bright, too. The G1 IS promising in most respects.
Do hope that despite the small aperture resulting from the use of TLS800, the EVF is still as bright and the enlarged image is still contrastive enough for focusing.
By the way, were the images in the LCD monitor captured using the 30x eyepiece and the pancake lens?
Regards,
Pete
Author: lwingkay    Time: 10/05/2010 23:23

Dear Chak Wing,

Re: Olympus pancake 25mm f2.8 for 4/3, need adaptor for using on Panasonic G1(setting at f4.5)

I asked this with some shopkeepers in Mong Kong's camera shops and was informed that the OM pancake 25mm could be used on the G1 direct and still be able to obtain auto focusing and auto metering functions. Wonder if these are really the case.

I presume that this OM pancake is also IF in design and that it is possible to link it to the DCA using the screw furrows for the filter on the front part of the lens.

Thanks in anticipation for answering.

Regards,
Peter Leung
Author: cwchan    Time: 14/05/2010 22:05

Quote:
Original posted by lwingkay at 10/05/2010 23:23
Dear Chak Wing,

Re: Olympus pancake 25mm f2.8 for 4/3, need adaptor for using on Panasonic G1(setting at f4.5)

I asked this with some shopkeepers in Mong Kong's camera shops and was informed that th ...
Sorry for reply late because not in Hong Kong.

(a)The Olymbus 25mm f2.8 is designed for 4/3 system, it needs a Olymbus MMF-1 (or2)adaptor before it can be used on its mini 4/3 system, like Pen or G-1 GH-1,,, etc. With this MMF-1 adaptor in place, it can perform auto-focus, auto-matering function fully.

(b)This pancake lens is not IF, the front group goes out and in during focus. You need a 43mm to 52mm aadaptor ring for joining the filter mount of the lens to the DCA. However, this may damage the gears inside the lens due to the weight of the body.

CW
Author: lwingkay    Time: 15/05/2010 07:06

Quote:
Original posted by cwchan at 14/05/2010 22:05


Sorry for reply late because not in Hong Kong.

(a)The Olymbus 25mm f2.8 is designed for 4/3 system, it needs a Olymbus MMF-1 (or2)adaptor before it can be used on its mini 4/3 system, like Pen or G ...
It is okay and many thanks for the information.  Pete



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