Samsung GX10 - 2x Convertor - What Focal Length Do I Need
Posted 02/02/2011 - 11:40
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Chris,
You put in 2x the focal length that you are using - so if you have the lens at 200mm, you put in 400mm. If zooming, then you could choose an "intermediate" value such as 250mm, but I would recommend sticking with the long end - I assume you are trying to increase the effective length of your lens, after all!
Remember that the teleconverter is also going to affect your exposure - a 2x teleconverter essentially makes your f5.6 lens an f11 lens, so you will need bright light or high ISO to get a reasonable shutter speed. The viefinder will be correspondingly dimmer, and if the converter supports autofocus your camera may struggle to lock focus. Of course, your effective focal length is now 400mm as well, so you will likely need a shutter speed of at least 1/500s if hand holding.
I wish you good luck - but suspect you will be disappointed. A teleconverter "degrades" image quality - especially a 2x converter (c.f. a 1.4x) - and the 50-200mm is not fantastic at the long end to start with. Teleconverters are normally only recommended for top quality prime lenses that have sufficient quality to handle the degredation. You might have more success trading in the samsung 50-200 and converter for the pentax 55-300, which is generally better regarded, and gets you 50% longer - or holding out for the (rumoured) WR version.
You put in 2x the focal length that you are using - so if you have the lens at 200mm, you put in 400mm. If zooming, then you could choose an "intermediate" value such as 250mm, but I would recommend sticking with the long end - I assume you are trying to increase the effective length of your lens, after all!
Remember that the teleconverter is also going to affect your exposure - a 2x teleconverter essentially makes your f5.6 lens an f11 lens, so you will need bright light or high ISO to get a reasonable shutter speed. The viefinder will be correspondingly dimmer, and if the converter supports autofocus your camera may struggle to lock focus. Of course, your effective focal length is now 400mm as well, so you will likely need a shutter speed of at least 1/500s if hand holding.
I wish you good luck - but suspect you will be disappointed. A teleconverter "degrades" image quality - especially a 2x converter (c.f. a 1.4x) - and the 50-200mm is not fantastic at the long end to start with. Teleconverters are normally only recommended for top quality prime lenses that have sufficient quality to handle the degredation. You might have more success trading in the samsung 50-200 and converter for the pentax 55-300, which is generally better regarded, and gets you 50% longer - or holding out for the (rumoured) WR version.
Posted 02/02/2011 - 12:43
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Quote:
pentax 55-300, which is generally better regarded
Taken with DA55-300 at 300mm;pentax 55-300, which is generally better regarded
With the 2x teleconvertor added, so 600mm;
IMHO a lot depends on the quality of the convertor in use, high quality ones can give good results, but the other end of the scale might as well be used as door stops. The point made by Adqam about lens quality is bang on though, the faster the better. Although once you start getting to 400mm and beyond a support is a good idea anyway.
Davex.
Posted 02/02/2011 - 18:02
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Thank you both for the info.
I tried 50-200 + convertor again earlier today, after giving the contacts a wipe and the menu didn't come up.
I looked on the settings screen menu and the OPS option was greyed out which according to the manual and the internet means that the focal length has been auto detected. The OPS setting also said Auto.
I bought the convertor to use at one specific track that I photograph at and that's Northampton International Raceway. To get over the catch fencing I need to stand on the home straight but I photograph the stock cars coming down the back straight and into turn 3 so I need that bit of 'extra length'.
Quite a few of the photos that I have published have been taken with the kit 50-200 lens that came with my GX10.
Regards, Chris.
I tried 50-200 + convertor again earlier today, after giving the contacts a wipe and the menu didn't come up.
I looked on the settings screen menu and the OPS option was greyed out which according to the manual and the internet means that the focal length has been auto detected. The OPS setting also said Auto.
I bought the convertor to use at one specific track that I photograph at and that's Northampton International Raceway. To get over the catch fencing I need to stand on the home straight but I photograph the stock cars coming down the back straight and into turn 3 so I need that bit of 'extra length'.
Quite a few of the photos that I have published have been taken with the kit 50-200 lens that came with my GX10.
Regards, Chris.
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285 posts
15 years
Derby ( UK )
I have got a 2x convertor which I intend to use with my Samsung GX10 and either the 50-200 kit lens or my Pentax 50-200WR lens from my K7.
I tried it earlier on and the focal length for the OPS ( Samsungs version of SR ) isn't 'auto recognised', the manual input screen comes up when I first turn the camera on.
What focal length do I need to input for a 50-200 lens with a 2x's convertor?
Regards, Chris.