Oly 45 1.8 with Pana GTC1 converter... works !!!

Started May 17, 2012 | Discussions
LMNCT Veteran Member • Posts: 4,908
Oly 45 1.8 with Pana GTC1 converter... works !!!
1

The new Telephoto converter from Panasonic, GTC1, works very well with the 45 f1.8 and creates a very light 180 mm 1.8 lens. I prefer it on the Oly rather than on the 14-42 GX lens for which it was designed.

 LMNCT's gear list:LMNCT's gear list
Panasonic LX100 Panasonic Lumix DMC-GM5 Panasonic Lumix DMC-GX7 Panasonic Lumix DMC-GX8 Panasonic G85 +23 more
drpoop
drpoop Regular Member • Posts: 449
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

I demand samples!

LMNCT wrote:

The new Telephoto converter from Panasonic, GTC1, works very well with the 45 f1.8 and creates a very light 180 mm 1.8 lens. I prefer it on the Oly rather than on the 14-42 GX lens for which it was designed.

 drpoop's gear list:drpoop's gear list
Olympus OM-D E-M5 Olympus M.Zuiko Digital 45mm F1.8 Rokinon 7.5mm F3.5 UMC Fisheye CS Panasonic Lumix G 20mm F1.7 ASPH Olympus M.Zuiko Digital ED 40-150mm 1:4-5.6 R +3 more
azazel1024 Senior Member • Posts: 1,139
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

Is it a 4x teleconverter? Or do you mean it is 180mm equivelent?

Bad news though, it is not 180mm f/1.8 equivelent, it is a 180mm f/3.6 equivelent. A 2x teleconverter results in a two stop loss of aperature. So the 45mm f/1.8 is actually a 90mm f/3.6 with a 2x teleconverter on there (I am not speaking of depth of field, I mean out right the aperature if f/3.6 with a 2x teleconverter on there).

 azazel1024's gear list:azazel1024's gear list
Sigma 30mm F2.8 EX DN +10 more
MAubrey
MAubrey Senior Member • Posts: 1,600
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!
1

azazel1024 wrote:

A 2x teleconverter results in a two stop loss of aperature. So the 45mm f/1.8 is actually a 90mm f/3.6 with a 2x teleconverter on there (I am not speaking of depth of field, I mean out right the aperature if f/3.6 with a 2x teleconverter on there).

That's only true when they're attached to the back of the lens. teleconverters attached to the front of a lens are an entirely different issue. Back-attaching teleconverters cause light loss because they move the lens groups further away from the sensor, but that doesn't happen in the case of ones that attach to the front.

-- hide signature --

--Mike

 MAubrey's gear list:MAubrey's gear list
Olympus OM-D E-M5 Sony a7 Olympus M.Zuiko Digital ED 75mm F1.8 Voigtlander 35mm F1.2 Nokton +2 more
leo9 Regular Member • Posts: 213
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

LMNCT wrote:

The new Telephoto converter from Panasonic, GTC1, works very well with the 45 f1.8 and creates a very light 180 mm 1.8 lens. I prefer it on the Oly rather than on the 14-42 GX lens for which it was designed.

That's interesting! How does it attach? I though it might have some kind of bayonet mount that only fitted the 14-42mm, but perhaps it just screws onto the 45mm?

 leo9's gear list:leo9's gear list
Sony a7 III Sony FE 55mm F1.8 Sony FE 70-200 F4 Sony Vario-Tessar T* FE 16-35mm F4 ZA OSS Zeiss Batis 85mm F1.8 +1 more
micksh6
micksh6 Senior Member • Posts: 2,613
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!
1

Good to know. I ordered mine few days ago and it's arriving tomorrow. I bought it specifically for Oly 45mm F1.8 to make 90mm F1.8 lens. I don't even have Pana X zoom.
I will also test it on 25mm F1.4, Oly kit zoom and long telezooms.

 micksh6's gear list:micksh6's gear list
Olympus PEN E-PL5 Olympus E-M1 Olympus M.Zuiko Digital ED 75mm F1.8 Olympus M.Zuiko Digital 45mm F1.8 Samyang 7.5mm F3.5 UMC Fisheye MFT +6 more
bab4 Regular Member • Posts: 455
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

Need pics!

 bab4's gear list:bab4's gear list
YI M1
azazel1024 Senior Member • Posts: 1,139
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

MAubrey wrote:

azazel1024 wrote:

A 2x teleconverter results in a two stop loss of aperature. So the 45mm f/1.8 is actually a 90mm f/3.6 with a 2x teleconverter on there (I am not speaking of depth of field, I mean out right the aperature if f/3.6 with a 2x teleconverter on there).

That's only true when they're attached to the back of the lens. teleconverters attached to the front of a lens are an entirely different issue. Back-attaching teleconverters cause light loss because they move the lens groups further away from the sensor, but that doesn't happen in the case of ones that attach to the front.

Not true in the least. The focal length with a 2x teleconverter, no matter WHERE it is placed in the optical assembly, doubles focal length. The physical Iris of the lens stays the exact same size. The 45mm lens has a 25mm Iris (45/25 = f/1.8), doubling the focal length to 90mm no matter how you do it results in a 90mm focal length, but you still have the same 25mm Iris as the Iris of the lens in this case is where the aperature blades are located (controlling the iris size). If the Iris placement where to somehow shift (which can't happen without changing the internal optics of the existing lens), the current physical obstruction of the aperature blades even when wide open would result is severe vignetting and the apertature blades would no long be able to control the light levels and DOF of the lens. The result 90mm/25mm = f/3.6.

 azazel1024's gear list:azazel1024's gear list
Sigma 30mm F2.8 EX DN +10 more
micksh6
micksh6 Senior Member • Posts: 2,613
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

azazel1024 wrote:

The physical Iris of the lens stays the exact same size. The 45mm lens has a 25mm Iris (45/25 = f/1.8), doubling the focal length to 90mm no matter how you do it results in a 90mm focal length, but you still have the same 25mm Iris as the Iris of the lens in this case is where the aperature blades are located (controlling the iris size). If the Iris placement where to somehow shift (which can't happen without changing the internal optics of the existing lens), the current physical obstruction of the aperature blades even when wide open would result is severe vignetting and the apertature blades would no long be able to control the light levels and DOF of the lens. The result 90mm/25mm = f/3.6.

Wrong. Front element size is what matters. Front-mounted converters have larger front element that the lens. I will post pictures to demonstrate DOF and background blur with and without converter. I used Oly TCON-17 on 45mm F1.8.

The only concern with Pana converter is that from specs its front element is very close to minimum required - 50mm, maybe a bit less, so there may be some vignetting.
Wait for OP's pictures.

 micksh6's gear list:micksh6's gear list
Olympus PEN E-PL5 Olympus E-M1 Olympus M.Zuiko Digital ED 75mm F1.8 Olympus M.Zuiko Digital 45mm F1.8 Samyang 7.5mm F3.5 UMC Fisheye MFT +6 more
micksh6
micksh6 Senior Member • Posts: 2,613
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

bab4 wrote:

Need pics!

I hope OP is working on pictures.

I suggest comparing background blur with and without converter (apart from sharpness, etc). Meanwhile I can post pictures taken with Oly 45mm and TCON-17 (what I called 75mm F1.8 lens last year, before Oly announced it).

Pana converter must provide better background separation (and it's 3 times lighter than TCON-17).

 micksh6's gear list:micksh6's gear list
Olympus PEN E-PL5 Olympus E-M1 Olympus M.Zuiko Digital ED 75mm F1.8 Olympus M.Zuiko Digital 45mm F1.8 Samyang 7.5mm F3.5 UMC Fisheye MFT +6 more
ginsbu Senior Member • Posts: 1,420
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!
 ginsbu's gear list:ginsbu's gear list
Olympus OM-D E-M5 Canon EOS M Olympus M.Zuiko Digital 14-42mm 1:3.5-5.6 II R Olympus M.Zuiko Digital 45mm F1.8 Panasonic Leica Summilux DG 25mm F1.4 +12 more
MT Senior Member • Posts: 1,943
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

Quick question

Have you this on BOTH the 14-42 GX? Why do you prefer it on the 45mm Oly? how's the sharpness and contrast across the entire frame?

Thanks,
MTMT

LMNCT wrote:

The new Telephoto converter from Panasonic, GTC1, works very well with the 45 f1.8 and creates a very light 180 mm 1.8 lens. I prefer it on the Oly rather than on the 14-42 GX lens for which it was designed.

Kuppenbender
Kuppenbender Senior Member • Posts: 2,141
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

azazel1024 wrote:

Not true in the least. The focal length with a 2x teleconverter, no matter WHERE it is placed in the optical assembly, doubles focal length.

I don't think MAubrey was disputing the idea that the focal length would be doubled.

The physical Iris of the lens stays the exact same size. The 45mm lens has a 25mm Iris (45/25 = f/1.8), doubling the focal length to 90mm no matter how you do it results in a 90mm focal length, but you still have the same 25mm Iris as the Iris of the lens in this case is where the aperature blades are located (controlling the iris size). If the Iris placement where to somehow shift (which can't happen without changing the internal optics of the existing lens), the current physical obstruction of the aperature blades even when wide open would result is severe vignetting and the apertature blades would no long be able to control the light levels and DOF of the lens. The result 90mm/25mm = f/3.6.

OP didn't mention anything about vignetting. I thought that was the point of his post. The tele-adapter works with the Zuiko 45mm.

As for doubling the aperture, I was also under the impression that front-fitting adapters don't affect it.

 Kuppenbender's gear list:Kuppenbender's gear list
Panasonic Lumix DMC-GX7 Panasonic Lumix G Vario 100-300mm F4-5.6 OIS Olympus M.Zuiko Digital 45mm F1.8 +3 more
azazel1024 Senior Member • Posts: 1,139
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

ginsbu wrote:

More technical explanation here:

http://ianperegian.com/My_FZ35_38_Webpage/Effect_of_Teleconverters_on_Aperture.html

Okay I stand corrected. I apologize.

 azazel1024's gear list:azazel1024's gear list
Sigma 30mm F2.8 EX DN +10 more
ginsbu Senior Member • Posts: 1,420
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

azazel1024 wrote:

ginsbu wrote:

More technical explanation here:

http://ianperegian.com/My_FZ35_38_Webpage/Effect_of_Teleconverters_on_Aperture.html

Okay I stand corrected. I apologize.

It's confusing stuff. I am continually needing to unconfuse myself about it. An important distinction that often trips people up is the difference between the physical aperture of a lens and its entrance pupil:
http://en.wikipedia.org/wiki/Entrance_pupil

That language isn't used in the the previous link, but the concept is relevant and the wikipedia explanation gets it across better.

 ginsbu's gear list:ginsbu's gear list
Olympus OM-D E-M5 Canon EOS M Olympus M.Zuiko Digital 14-42mm 1:3.5-5.6 II R Olympus M.Zuiko Digital 45mm F1.8 Panasonic Leica Summilux DG 25mm F1.4 +12 more
OM User
OM User Regular Member • Posts: 290
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

Sounds like one of these may be just the job.
Thanks for the explanation.

 OM User's gear list:OM User's gear list
Olympus OM-D E-M5 Olympus PEN E-PM2 Olympus M.Zuiko Digital ED 12-50mm 1:3.5-6.3 EZ Olympus M.Zuiko Digital ED 12mm 1:2 Olympus M.Zuiko Digital ED 75-300mm 1:4.8-6.7 +10 more
OP LMNCT Veteran Member • Posts: 4,908
Re: Oly 45 1.8 with Pana GTC1 converter... works !!!

I have confused you. I am speaking in "35mm Speak". The 45 1.8 is actually a 90mm in 35 Speak...hence, 2X 90 = 180mm...and it is f 1.8. I think the 45 1.8 is sharper than the 14 - 42 GX at full extension (ie 42..or, 84 in 35 Speak). And I also prefer the 14 2.5 (which is a 28mm in 35 Speak) with the GWC1 wide converter...I am not totally in love with the 14 -42 GX.

 LMNCT's gear list:LMNCT's gear list
Panasonic LX100 Panasonic Lumix DMC-GM5 Panasonic Lumix DMC-GX7 Panasonic Lumix DMC-GX8 Panasonic G85 +23 more
MT Senior Member • Posts: 1,943
LMNCT

LMNCT,

Thanks. Actually I would love to hear you comment on how this converter performs with the 45mm 1.8. That would be 180mm equivalent at '35 speak'. I wonder how it performs at f1.8. Then f2.5.

Thanks,
MTMT

LMNCT wrote:

I have confused you. I am speaking in "35mm Speak". The 45 1.8 is actually a 90mm in 35 Speak...hence, 2X 90 = 180mm...and it is f 1.8. I think the 45 1.8 is sharper than the 14 - 42 GX at full extension (ie 42..or, 84 in 35 Speak). And I also prefer the 14 2.5 (which is a 28mm in 35 Speak) with the GWC1 wide converter...I am not totally in love with the 14 -42 GX.

OP LMNCT Veteran Member • Posts: 4,908
Re: LMNCT
1

The GTC1 has no effect on the sharpness of the 45 1.8. All it does is extend the range. It really is excellent because the 45 is light, so is the converter...a lightweight, tack sharp and affordable 180 f 1.8 is a great addition to anyone's kit !!!

 LMNCT's gear list:LMNCT's gear list
Panasonic LX100 Panasonic Lumix DMC-GM5 Panasonic Lumix DMC-GX7 Panasonic Lumix DMC-GX8 Panasonic G85 +23 more
Gregm61 Forum Pro • Posts: 15,362
Re: LMNCT

LMNCT wrote:

The GTC1 has no effect on the sharpness of the 45 1.8.

I've seen claims like this before. When the images get posted, another truth comes out. No adapter that adds optical elements to the primary lens have no affect on image quality. None. Not even the best true teleconverters. At the very least corners become degraded, but post some full resolution images and shows us that's not so.

Panasonic does make some excellent accessory lenses. No doubt that probably is the best option for doing this. When I was shooting an FZ50 I used their DMW-LW55 lens which converted the 35mm wide end to a much wider 24mm and was excellent, but not without faults. The program PTLens has a great profile for dealing with the distortion that combination produces.

-- hide signature --

"There's shadows in life, baby.." Jack Horner- Boogie Nights

 Gregm61's gear list:Gregm61's gear list
Olympus E-M1 Leica M9 Leica M (Typ 262) Olympus E-M1 II Leica M-P (Typ 240) +34 more
Keyboard shortcuts:
FForum MMy threads