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12-04-2007, 01:23 PM   #1
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A 70-210mm F1:4 with teleconvertor ?

This is probably a newbie question but better safe the sorrow.

I've been reading some sites on Bird photography and they mostly recomend a lens wit ha focal lenght of 500mm (or more).

now since I don't have the money for a Sigma 500mm EX DG F: 4.5 Pentax AF I was thinking of adding a TC to my "new" old Telezoom lens.

my local store only has 2 Pentax compatible Teleconvertors (I guess the USA and Asia are bigger markets for Pentax the Europe since we seem to be dominated by Nikon and Canon). :

- Sigma Teleconverter 1.4X DG APO Pentax
- Sigma Teleconverter 2.0X DG APO Pentax

now as I understand it correctly this would bring my focal range to eighter :

1.4 : 70-210 for 35mm -> 105-315mm dSLR -> 147-441mm TC 1.4
2.0 : 70-210 for 35mm -> 105-315mm dSLR -> 210-630mm TC 2.0

Now the questions are :

- Is my math correct and does this actually work (I read on the stores website that the Aperture of the lens goes up F2.5 to F4)

- Would this be a good idea for this "old" manual focus lenght (since most people sugest a fast autofocus lens and setting the camera to AF-C (continuous)


I'm not sure if I want to focus on bird photography at the moment, My main interest is nature so both Landscape and animals are included but I don't want to spend a lot of money on an expensive tele or zoom lens to maybe find out later that it's not my thing.

Anyways, since the store has a limited range of Pentax glass (does Tamron make Telezoom lenses ?? since I don't see any of those at my store only Widezoom lenses that go from 28 to 200 and 300mm but I read these are bad since the range is to high).

could someone advise me on the following lenses (quality and such).

- Sigma 55-200mm DC F: 4.0-5.6 Pentax Digitaal
- Sigma 70-300mm APO DG Macro F: 4.0-5.6 Pentax AF
- Sigma 135-400mm DG F: 4.5-5.6 Pentax AF

- Pentax SMC-DA 50-200mm F:4.0-5.6 ED
- Pentax SMC-DA* 50-135mm F:2.8 ED IF SDM

- Tamron AF 28-200mm F:3.8-5.6 XR Di Asp.Mac. Pentax
- Tamron AF 28-300mm XR F:3.5-6.3 Di Asp.Mac Pentax
- Tamron SP AF 28-75mm XR F:2.8 Di LD Asp. Pentax
- Tamron AF 18-200mm F:3.5-6.3 XR Di II Pentax
- Tamron SP AF 17-35mm XR F:2.8-4.0 Di LD Asp.Pentax
- Tamron AF 18-250mm F:3.5-6.3 XR DiII LD Asp.Pentax

based on this I would think the Sigma lenses are the best or maybe the DA* but that's also the most expensive one in the list

so all advise (information) is welcome.

12-04-2007, 02:15 PM   #2
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I have an SMCP-A 70-210/4 and a Pentax A 1.4xS. the combination works reasonably well, but the A 70-210 is not by any means a * lens. When you put an extender on a lens you magnify not only the image, but also the lens weaknesses. You lose 1 stop with a 1.4X and 2 stops with a 2x. The lens quirks get worse with the 2x because they are magnified more.

I would like to add my comments to some of the things you have been reading.

1. I use a slow, manual focus, 400mm lens (SMCP-M 400/5.6) for my bird pictures.

2. For small birds, I use the 1.4xS extender with it, which gives me a 560/8. This extender is ill matched to the 400, but the L extender will not go into the barrel of this old lens so I cannot use it at all. (The 1.4xL extends into the barrel of the lens) I uploaded one image to the user gallery here
User Photo Gallery - Nature

3. I tried the Sigma 170-500 AF, and found that it focused more often on some twig or branch than on the eyes of the bird. I sold it and went back to the 400.

4. "You must have" is a really overdone concept. If you can only afford the extender and your current, outdated, allegedly useless 70-210, use them. If you enjoy the pictures that result, and don't "pixel peep" all the better. When you win the lottery, go out and buy that SMCP-FA* 600mm f/4 lens. One of my favourite macro shots was taken with a (shudder) Sigma 75-250 with the matched 2x close up lens (shudder) on it on a KX hand held (shudder). It isn't a sharp, crisp and superbly in focus image, but I have an 8x10 with a 4 inch (10 cm) long honey bee on a flower in my mother's garden.

Last edited by Canada_Rockies; 12-04-2007 at 02:24 PM. Reason: Added URL to Gallery for song sparrow
12-04-2007, 04:47 PM   #3
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i too tried mine out recently with a A2x-s also. while the 70-210 is one of my favorites because of it's sharpness i was diappointed with the TC. images just got too soft for my liking and it took too much PP to get something close to acceptable. i never really been too happy with a TC on a zoom.





12-04-2007, 04:49 PM   #4
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It all depends on how large a print you want to make.

12-04-2007, 04:59 PM   #5
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oyu could also ch out the pentax 500/4.5 . it's IQ is superb for a 30+ year old lens and can be found fo 400-800usd. mine is down right now but i'm using a tamron 300/2.8 with their matched extenders. these TCs are superb except they only work on tamron's adaptall lenses.. also, remember that anything over 300mm and you'll probably need a steady tripod and head.

tamron 300mm/with the 200f 2x TC...... forget about ever finding one of these 2x.

12-04-2007, 05:59 PM   #6
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Here's one I got a couple weeks ago with the a 70-210 f4 and kenko 1.5x tc not real good cause of the sun behind but ok i guess. It is a bald eagle looking quite miserable- I think he's molting
12-05-2007, 03:15 AM   #7
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QuoteOriginally posted by Canada_Rockies Quote
4. "You must have" is a really overdone concept. If you can only afford the extender and your current, outdated, allegedly useless 70-210, use them. If you enjoy the pictures that result, and don't "pixel peep" all the better. When you win the lottery, go out and buy that SMCP-FA* 600mm f/4 lens.
Thanks for the advise.
Well at the moment I can't spend someting like 800 euro or even more on a lens, and I don't think I'm even "ready" for one of those. I mean I'm still very green to all of this so getting a 3000 euro lens (like a 500mm prime) looks a bit like overkill at the moment and I'll probably not make any better pictures with it then with the Kitlens or the 70-210mm one.

So I think that it would even turn out negative since you have a quality lens but still take crappy pictures so it's not a good motivation. Offcourse with a bad lens it would be the same but from what I understand the 70-210 is not a bad lens and with the 1 stop loss of the 1.4x I guess it's still pretty good.

I don't "pixel peep" (at least not that I know) and I'm not planning on printing them (specially not larger then a standard photo, I think that's 10x15cm ??) but I do like them to show up sharp on my 19inch Desktop monitor.

I do this for myself and if I decide to upload to someplace like Flickr or Zenfolio these services resize the pictures to a smaller size so the pictures looks sharper/better then anyways (or not).

I took this next picture the day I got my 70-210 lens from the eBay seller :



I guess it's not a High Quality pictures (composition and not fully focused on the bird) but I guess it looks fairly well for website.

the full size photo is here

the Image is ehanced with Lightroom since it was a bit underexposed and I did some color toning (make some of the yellow in the bird a bit brighter).

And this brings me to an additional question.

I've been reading that dusk or dawn in the best moment for shooting (birds) but this one was taken around 10 or 11 am on a very clowdy (overcast) day so I think that the moment was wrong since there was no sun and less color (more grey).

so what's the best moment to shoot birds is it dawn in the summer when the sun is nice and yellow/orange and/or can it also be done during a fall/winters day (overcast or not) ??

I guess using a flash might help but I don't want to scare the birds with a bright external flash (don't have one at the moment) or with the build-in flash.

Well, I guess I'll investigate (at the store) on the 1.4x TC and see what I can do with it (like you said, I can always upgrade to a more expensive lens when I win the lottery).
12-05-2007, 06:02 AM   #8
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QuoteOriginally posted by borno Quote
Here's one I got a couple weeks ago with the a 70-210 f4 and kenko 1.5x tc not real good cause of the sun behind but ok i guess. It is a bald eagle looking quite miserable- I think he's molting
Hi,
do you have teleconverter Kenko AF 1.5x Teleplus SHQ ?
This picture looks very good... do you have some more shots with this TC Kenko 1.5?
Salute.

12-05-2007, 02:05 PM   #9
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Hey jazzer,
thats the one, shq 1.5x I don't use it much because I have a tamron 300mm adaptall that has it's own teleconverters but it's not bad. here's another from the same morning.
12-05-2007, 03:11 PM   #10
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I hear that 1.5 Kenko is good teleconverter... I wanna buy one for myself
I am planing to use it with DA*50-135/2,8 or some another telezoom lens

Last edited by JAZZer; 12-06-2007 at 06:51 AM.
12-06-2007, 07:44 AM   #11
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QuoteOriginally posted by JAZZer Quote
I hear that 1.5 Kenko is good teleconverter... I wanna buy one for myself
is it suposed to be better then the Sigma's I've posted in my question ??

If it IS indeed (much) better then the Sigma I might ask the people at my local store if they can get it (their Pentax stuff is fairly limited so it seems but they mainly sell Canon and Nikon I guess).
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