Teleconverter help

[Icemann]

The guy from Adorama was no help. I have written to Tamron but I know you guys will get me the right answer faster.Does the lens have to be 50mm or larger to work.I'm thinking of buying a Tamron 1.5xTeleconverter for an upcoming trip and I'm to cheap too spend several thousand dollars on a 500mm telephoto.I plan on using it on a Nikon D3000 with the Tamron 18-270mm lens and also wondering if all the camera auto functions will work with the teleconverter attached? Thanks in advance for any and all help

 

[ukcatfan]

You typically need a fast lens to use one. A prime lens is best. I would be extremely surprised if it worked with your lens. If it even mounted correctly, communicated correctly, etc, there is no way that there is going to be enough light for it to AF at anything but the wide end.

 

[jann1033]

You typically need a fast lens to use one. A prime lens is best. I would be extremely surprised if it worked with your lens. If it even mounted correctly, communicated correctly, etc, there is no way that there is going to be enough light for it to AF at anything but the wide end.

my tamron pro 1.4 supposedly needs at least f4 and 100mm but i can and have used it with my canon f4 70-200... though also be aware you will need a tripod since it's really like 280mm on a 200 lens and every wiggle shows up( on canon not sure if there is a crop factor on your camera). i never had a problem with it recognizing any electrical operations on my xt, only problem i have had is it either it doesn't work well with my 40d or something is wrong with it...I had only used it a few times total but it caused an error message then my camera's AF went out permanently( it was a refurb but recently purchased so i don't know if it was a problem with the camera or the converter and the company just replaced the body). at first tamron said it wouldn't cause that, then told me not to try it on my new camera in case it did cause it(??????? talk about them talking out of both sides of their mouth on that one lol) I'm going to send it in to see if it is working or not but it's only a yr warranty( unlike their usual 6 yr) so out of warranty
if you get the tamron make sure you get the pro model if they still make the cheaper one also, it's supposed to be a lot sharper. mine is 140f-ca...guessing yours would be "n" something at the end

 

[MarkBarbieri]

I would guess that, in addition to having very little light to focus with, a shot taken on a super zoom with a teleconverter would look like poop (unless it was a picture of poop). There is a reason why people pay a gazillion dollars for those giant lenses. You can trade some image quality for extra reach with a teleconverter, but I don't think that a lens with a 10x zoom range is likely to have much left to trade with. You would probably be better off just cropping to get the extra reach.

 

[jann1033]

mark is right , you need a good sharp lens to start with or you will end up with what mark said. that is probably why uk made the prime lens comment. they are usually sharper than zooms...i can get away with my phoenix 100mm toy lens but it is a sharp lens and a prime but usually used it with my 70-200 which is an l lens

 

[ukcatfan]

mark is right , you need a good sharp lens to start with or you will end up with what mark said. that is probably why uk made the prime lens comment. they are usually sharper than zooms...i can get away with my phoenix 100mm toy lens but it is a sharp lens and a prime but usually used it with my 70-200 which is an l lens

Also b/c the Tamron 18-270 is f/6.3 at the long end and only f/3.5 on the wide end. With the stop loss of the converter, there simply will not be enough light entering the lens to AF. I have always heard that it is best to have a f/2.8 or faster lens if using a converter.

 

[Icemann]

Also b/c the Tamron 18-270 is f/6.3 at the long end and only f/3.5 on the wide end. With the stop loss of the converter, there simply will not be enough light entering the lens to AF. I have always heard that it is best to have a f/2.8 or faster lens if using a converter.

Thank you for your help this all makes sense now,I'll not be ordering this.Now I have to figure out how to come up with 25k for plan B Thanks Again

 

[jann1033]

Also b/c the Tamron 18-270 is f/6.3 at the long end and only f/3.5 on the wide end. With the stop loss of the converter, there simply will not be enough light entering the lens to AF. I have always heard that it is best to have a f/2.8 or faster lens if using a converter.

you couldn't use it at all then with that lens as it's to short at the 3.5 and to small at the 270...you should be able to find something a little cheaper than 25 k thought
the 1.4 adds 1 stop to the lens so even with an f4 it's not bad if you are outside in decent light, which i think would be most places you would use it if you are looking for nature shots. i think kenko and tamron are the only 2 that will use f4, the others were f2.8 ( i think the kenko and tamron are or at least were the same converter when i was looking in 2007, just rebadged iirc so i went with the tamron which was cheaper)