Teleconverters questions

[boroangel]

Hi guys, I am using a S5500 now with a 10x zoom but I am thinking of increasing it by adding teleconverters (expanding the focal length). I have some questions though so hope some experts can enlighten me.

1. Adding TC doesnt technically increase the zoom, more the focal length, say 35-135 become 70 to 270 with a 2x zoom. So that means the object when u zoom to full will be 2 times in size with the TC? However, that also means that the object u taking with least zoom eg. at 70mm will also be twice in size?

2. I heard there are problem with TCs in terms of vignatting (wrong spelling) that means got dark rings around the object? And I also read that with TCs you must zoom to full to take the pic? Say I add on a 1.5X Tc to an original 10X zoom, can I take the pic at 13X zoom instead of the full zoom at 15X? Sorry I should mention in terms of focal distance but i lazy to calculate.

3. Adding TCs is also very dependent on the aperture settings of your camera? I think I have read about it before but dont quite understand it. Cos for each camera there are 2 ranges of aperture settings given, one for wide zooms and one for tele right? I suspect its got to do with the amount of light coming in to the camera when you add on Tcs and you have to compensate by adjusting the aperture? Depending on the allowable range of the apeture on your DC, it will affect the kind of TCs you can get?

4. I also read that some TCs with 2X zoom also technicallly doesnt achieve that....prob only reach around 1.6 to 1.8?

5. When we buy a Tc, to see if its compatible with our DC, do we only look at the thread size, for example 55mm?

6. Lastly, can anyone recommend a 2x TC for my S5500? cos in my manaual the Tc was recommended as TL-FX9 which is only 1.5X.

[shawnlim]

With 2X TC attached in front of your 10X lens does not give you 20X zoom, its is only 10X + 2X. If its attached to a SLR body than the lens, then its 20X.
Hopefully i m correct

[mpenza]

Originally Posted by boroangel Hi guys, I am using a S5500 now with a 10x zoom but I am thinking of increasing it by adding teleconverters (expanding the focal length). I have some questions though so hope some experts can enlighten me. 1. Adding TC doesnt technically increase the zoom, more the focal length, say 35-135 become 70 to 270 with a 2x zoom. So that means the object when u zoom to full will be 2 times in size with the TC? However, that also means that the object u taking with least zoom eg. at 70mm will also be twice in size?

The object will be four times bigger in terms of area on the image.

Originally Posted by boroangel 2. I heard there are problem with TCs in terms of vignatting (wrong spelling) that means got dark rings around the object? And I also read that with TCs you must zoom to full to take the pic? Say I add on a 1.5X Tc to an original 10X zoom, can I take the pic at 13X zoom instead of the full zoom at 15X? Sorry I should mention in terms of focal distance but i lazy to calculate.

It's vignetting. Usually, you'll get no vignetting at the tele end of the zoom. Depending on the size of the teleconverter used, you may even get no vignetting at the wide end of the zoom.

Originally Posted by boroangel 3. Adding TCs is also very dependent on the aperture settings of your camera? I think I have read about it before but dont quite understand it. Cos for each camera there are 2 ranges of aperture settings given, one for wide zooms and one for tele right? I suspect its got to do with the amount of light coming in to the camera when you add on Tcs and you have to compensate by adjusting the aperture? Depending on the allowable range of the apeture on your DC, it will affect the kind of TCs you can get?

This refers more to SLR type of teleconverters where the teleconverter is mounted between the camera body and the lens. For your case, the teleconverter is mounted in front of the lens. There will be some light loss but you only need to compensate when the metering is not done through the lens (e.g. flash metering with external flash).

Originally Posted by boroangel 4. I also read that some TCs with 2X zoom also technicallly doesnt achieve that....prob only reach around 1.6 to 1.8?

Many so-called 2x teleconverters are only 1.3x to 1.5x.

Originally Posted by boroangel 5. When we buy a Tc, to see if its compatible with our DC, do we only look at the thread size, for example 55mm?

Not just the thread size. You can mount bigger or smaller threadsize teleconverters with the appropriate step-up or step-down rings. Best is to mount the teleconverter and try.

Originally Posted by boroangel 6. Lastly, can anyone recommend a 2x TC for my S5500? cos in my manaual the Tc was recommended as TL-FX9 which is only 1.5X.

Got for Olympus TCON17 1.7x teleconverter which costs ~$140. There is no good 2x that cost $140 or below that is a true 2x and gives as good quality as the TCON 17.

[mpenza]

Originally Posted by shawnlim With 2X TC attached in front of your 10X lens does not give you 20X zoom, its is only 10X + 2X. If its attached to a SLR body than the lens, then its 20X. Hopefully i m correct

Incorrect. With a real 2x tele attached in front of a digicam 10x lens, you'll get 20x equilvalent at the tele end.

Anyway, technically speaking the zoom ratio always stays at 10x for both SLR and digicams since the wide angle end is also "multiplied".

[boroangel]

Originally Posted by shawnlim With 2X TC attached in front of your 10X lens does not give you 20X zoom, its is only 10X + 2X. If its attached to a SLR body than the lens, then its 20X. Hopefully i m correct

This cant be true?

[shawnlim]

Originally Posted by mpenza Incorrect. With a real 2x tele attached in fron of digicam lenses, you'll get 20x.

My bad

[boroangel]

Quote: The object will be four times bigger in terms of area on the image.

Yes I heard it should be 2 times in length and 4 times in area. What about the sharpness of the image, will it be as sharp as when u use it without the TC, in terms of no blurred images?

Quote: It's vignetting. Usually, you'll get no vignetting at the tele end of the zoom. Depending on the size of the teleconverter used, you may even get no vignetting at the wide end of the zoom.

Will you get vignetting somewhere in between the tele and the wide end? If so is there any way to rectify it?

Quote: This refers more to SLR type of teleconverters where the teleconverter is mounted between the camera body and the lens. For your case, the teleconverter is mounted in front of the lens. There will be some light loss but you only need to compensate when the metering is not done through the lens (e.g. flash metering with external flash).

Could you explain a bit about metering.....dont quite understand this part...by the way I dont have a hotshoe for an external flash.

Quote: Got for Olympus TCON17 1.7x teleconverter which costs ~$140. There is no good 2x that cost $!40 or below that is a true 2x and gives as good quality as the TCON 17.

I heard its recommended to get teh same Tc as the DC to get good quality images, is it true?

[mpenza]

Originally Posted by boroangel Yes I heard it should be 2 times in length and 4 times in area. What about the sharpness of the image, will it be as sharp as when u use it without the TC, in terms of no blurred images?

Use a low quality one and your images will be blur. Use a high quality one and the images will be as sharp as u use it without the TC.

Originally Posted by boroangel Will you get vignetting somewhere in between the tele and the wide end? If so is there any way to rectify it?

Yes. That's the usual case. No way to rectify.

Originally Posted by boroangel Could you explain a bit about metering.....dont quite understand this part...by the way I dont have a hotshoe for an external flash.

It's ok then.

Originally Posted by boroangel I heard its recommended to get teh same Tc as the DC to get good quality images, is it true?

Generally so. But Olympus ones are pretty good, that's why I recommended them. I used one with my Fujifilm S602Z too.

[boroangel]

Thanks...I will keep the Olympus TCON17 1.7x teleconverter in view.

[boroangel]

May I know why there are TCON 17 and TCON 17C?
Cos under the specifications it was stated that TCON 17C is made specially for Olympus cameras. So that that mean it cant be used for my Fuji S5500?

[kababoom]

Originally Posted by shawnlim My bad

Hi! so is is true if i attached an 1.7x tele lens on my fz20 i can get 20.4x optical zoom?

[roti_prata]

from personal experience, its not advisable to get tc for such big zoom cameras. the image quality is already not very good at the ends and adding tc will only worsen it. even for pro tele-converters for slr cameras, 2x degrades image quality considerabily. most people use 1.4x or 1.7x. ur s5500 goes out to 350mm if im not wrong, adding a tc will extend it to 700mm. is this really necessary? at such magnification, the camera must be very stable, preferably mounted on good tripods(those without the cross beam connecting the legs and center column) u can forget about hand holding. i'ved used a s5000 with sony 2x tc. vignetting is very bad and so is purple fringing. depending on the quality of the tc, 50% cropping may even yield better results.

[roti_prata]

the how-many-times zoom is a relative concept. it is the maximum focal length divided by the minimum(usually 35mm). like my nikon 70-200vr is only 2.9x but its a tele-zoom while a 17-55 at 3.2x is a wide-zoom.