Kenko Teleplus PRO 300 AF 3X for Canon

[alvaro_morales]

Hi, I just got a Kenko Teleplus PRO 300 AF 3X for Canon, I am new on

photography, and I got a question.

On internet, I read that this teleconverter has 4 groups/7 elements.

Can somebody explain to me what does these 4 groups and 7 elements mean?

Please, I would like to take full advantage of the teleconverter, so please

send me a message.

 

Thank you.

[rainer_t]

Alvaro,

 

the term X elements in Y groups mean ... the lens/converter or whatever it is has X discrete lenses (or optical elements) that are grouped to Y groups. A group can consist of one ore more lenses. If its more than one lens in a group, they can be cemented together.

 

To 'take full advantage' the knowledge of that is not required. Just use the TC whenever you feel you should.

 

Especially with a 3x TC you should be aware, that your camera body will loose the ability for AF (with most lenses) while you use the

TC so you will need to focus manually.

 

Rainer

[alvaro_morales]

Thank you very much Rainer!

But I still have one more question... I really don't want to bother you with my questions, but can you tell me how is the qality image for the teleconverter I have? To be honest with you, I don't see any difference on my shots(but I am not a pro, so what do I know...)so, can you tell me if it affects the quality, or just the light stops, or what...

I bought it used for $85, was that a good deal?

I will be waiting for your answer.

 

Thank you again.

[rainer_t]

Alvaro,

 

Well, you don't use a TC to get better imagequality ...

 

If you have 2 lenses, a good 100mm and a good 300mm and this 3*TC, the 300mm lens will certainly deliver better imagequaliy than the 100mm plus the 3*TC will. But, the reason you use a TC is, that you don't have a longer lens. So, imagequality is usually not the question (because to take a certain image, you either use the TC, or you don't get the image, at least not in the way you wanted).

 

The price sounds like a good deal to me. Qualitywise, as said, a TC cannot compete with a longer lens, it will always be a compromise.

 

It doesn't matter if you're a pro or not ... if the images you get with the TC are good for you, then things are perfect. You take the images, so you're the first person to judge.

 

Rainer

[alvaro_morales]

Thank you again Rainer!!!

I will keep in mind what you just told me...and you're right, I need the TC becuase the lens I have is a 28-90mm, so I need it to get at least a 270mm.

Thanks again for the information.

I really appreciate it.

 

God Bless!!!

[alex_lofquist]

With a 3X TC you're going to lose over 90% of your light, or more than three stops! (89% based on the magnification and at least another 2% or 3% from the additional glass in the optical path.) Any errors in focussing, or aberrations in the original image will now be magnified by three diameters. If you don't expect much, you will not be disappointed.

[rainer_t]

Alvaro,

 

typically teleconverters are designed to extend tele-lenses.

So the results with a 'normal' range zoom like the 28-90 will

not be as good as if it would be combined with a real telelens.

(But then again, why does one use a 3* TC rather than a 2* or a 1.4*)

 

The problem will more likely be this: Your lens has f/5.6 at the long end. So, combined with the TC you have a 270mm f/16. Without a tripod, you should use at least a 1/250sec (better 1/500) as exposure time.

f/16 and 1/250sec with 100iso equals 16EVs ... A bright sunny day has only 15EVs ... therefore, you cannot use this TC without a tripod, or without a faster film. I mean, yes you can use it, but the pictures will be blurred due to camera shake.

 

Rainer

[andrew robertson]

You don't want to use a 3x TC with that lens. If you REALLY NEED to get to at least 270mm

(seems a bit arbitrary) return the TC and get an older, used M42 'screw mount' 300mm

prime lens. It will let in much more light and have much better image quality, and will also

probably be cheaper than your TC was.