New to Pentax from the Canon Camp Pentax equivalent to Canon 70-200mm f/4 L

Pentaxor · 12-17-2009, 12:20 AM

Originally posted by frank2001

Hi all.
I am an advanced amateur and have been for many many years.
I've been a Canon DSLR user since the D30.
I have wanted to downsize and made several unsuccessful attempts with Rebels, Olympus 4/3, Panasonic and Olympus micro 4/3 and my large hands just don't lend themselves well to those tiny grips and I miss the optical viewfinder.
Also, I don't shoot nearly as much as I used to and have way too much money invested in my Canon stuff.
I ordered a K-x today based on many opinions and reviews and the fact that it comes in White!
I hope it's the answer.
I've read the kit lens is pretty good so...
First thing I'll need is a tele lens.
I currently use a Canon 70-200mm f4 and haven't figured out the Pentax equivalent so any suggestions would be welcome
Frank

Hi Frank ! Welcome to Pentax Forums. If you are looking for something that is equivalent or better than the Canon 70-200 F4, I suggest that you get the Pentax Primes. I know they are not zooms but I could say they are the best of the bunch for Pentax. and also they are much faster than F4. the lens recommendations would be an FA31, FA77, and FA135/2.8 or better the K135/2.5. I believe you will be more than satisfied once you get to try this lens. mind you that I have tried those 3 lenses. 2 of which I can't afford right now and one which just I wasn't able to acquire due to an unfortunate incident.

PentaxPoke · 12-17-2009, 12:27 AM

Originally posted by wallyb

No joke, the Tamron is generally better in sharpness, not even factoring cost in. Even with "L" in the title, it's still made from the same elements as other lenses, and Tamron has been in the game for a very long time as well.

Are you both getting that from that article? Here is the main part of the conclusion:

"If you don't mind the lack of image stabilization, I'd recommend the Sigma, it is much cheaper than the Canon and it has better autofocus than the Tamron. Overall the Canon is the best, but it is way more expensive, so you have to evaluate if it is worth the price depending by your esigencies."

You also didn't read the link I attached regarding the Tamron sharpness at the edges, and AF slowness and inconsistency. Finally, you are comparing the wrong lens. The OP said he had the 70-200 f/4 not the 2.8. That is the specific lens I was talking about. They are different. "The sharpest zoom I ever used." -Ken Rockwell (Noted Nikonian)

I have used the 70-200 f/4 myself, and it was an eye-opening experience.

Oh well, this is a Pentax forum anyway, and we are getting off track...

wallyb · 12-17-2009, 12:33 AM

Originally posted by PentaxPoke

Are you both getting that from that article? Here is the main part of the conclusion:

"If you don't mind the lack of image stabilization, I'd recommend the Sigma, it is much cheaper than the Canon and it has better autofocus than the Tamron. Overall the Canon is the best, but it is way more expensive, so you have to evaluate if it is worth the price depending by your esigencies."

You also didn't read the link I attached regarding the Tamron. Finally, you are comparing the wrong lens. The OP said he had the 70-200 f/4 not the 2.8. That is the specific lens I was talking about. They are different. "The sharpest zoom I ever used." -Ken Rockwell (Noted Nikonian)

Oh well, this is a Pentax forum anyway...

You're asking me if I read links? Oof...

I guess you didn't read the one posted in reply to you by LeDave:

Juza Nature Photography

Now, which site am I more inclined to believe... one with direct visual comparisons of four lenses side by side, or one without them... and *with* a canon camera on their front page... and the word "Canon" sprinkled out in every other link... and called "Canon Digital Lens Reviews"...

And don't get me started on Ken Rockwell!

PentaxPoke · 12-17-2009, 12:37 AM

Originally posted by wallyb

You're asking me if I read links? Oof...

I guess you didn't read the one posted in reply to you by LeDave:

Juza Nature Photography

Now, which site am I more inclined to believe... one with direct visual comparisons of four lenses side by side, or one without them...

I did read that one from LeDave, and I just quoted the conclusion from his link that said the Canon was the best!

Also, I sent you a link to a site that has direct comparisons of both! You have to click the comparison. Here I did it for you:

Canon EF 70-200mm f/4.0 L IS USM Lens - Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Comparison - ISO 12233 Resolution Chart Results

wallyb · 12-17-2009, 12:41 AM

Originally posted by PentaxPoke

I did read that one from LeDave, and I just quoted the conclusion from his link that said the Canon was the best!

Also, I sent you a link to a site that has direct comparisons of both! You have to click the comparison. Here I did it for you:

Canon EF 70-200mm f/4.0 L IS USM Lens - Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Comparison - ISO 12233 Resolution Chart Results

"but while the Canon and the Tamron are close (actually, the Tamron is slightly sharper)"

From the Juza Nature Photography link. Maybe you missed that line? And again, I'm not sure what value there is in comparisons from a clearly Canon-sponsored, or at least Canon-biased, review site...

Edit: and the center sharpness of the Tamron lens looks better in the link you gave me there... visually at least, though of course their review states otherwise. And I think anyone would expect a lens with a starting aperture of f/2.8 to perform worse on the corners than one that starts at f/4, even at the same aperture.

LeDave · 12-17-2009, 12:49 AM

Originally posted by PentaxPoke

I did read that one from LeDave, and I just quoted the conclusion from his link that said the Canon was the best!

Also, I sent you a link to a site that has direct comparisons of both! You have to click the comparison. Here I did it for you:

Canon EF 70-200mm f/4.0 L IS USM Lens - Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Comparison - ISO 12233 Resolution Chart Results

Yeah but we were speaking of IQ here at first.

But I see now you are moving onto more than just that for the favor of the Canon winning. Other than that what you did leave out was he stated the Canon was best after speaking of AF and build quality, only to conclude saying "actually, the Tamron is slightly sharper".

So in terms of starting out what the argument was about, the Tamron does win out in IQ, but I do agree by it's "L" quality built lens, the Canon is better in it's own but at nearly twice the cost if IS is included.

Pentaxor · 12-17-2009, 01:02 AM

honestly speaking, the IQ of the "L" lenses can be matched by any maker. some are even slightly or a tad better than the "L" lenses when it comes to sharpness and rendering.

what does make the "L" lenses stand out from the rest is it's build and AF function. that's it.

let's face it. some people would tend to say that the IQ of the "L" lenses are unmatched inorder to validate their reason for buying a very expensive lens.

wlachan · 12-17-2009, 01:21 AM

Originally posted by Pentaxor

honestly speaking, the IQ of the "L" lenses can be matched by any maker. some are even slightly or a tad better than the "L" lenses when it comes to sharpness and rendering.

what does make the "L" lenses stand out from the rest is it's build and AF function. that's it.

let's face it. some people would tend to say that the IQ of the "L" lenses are unmatched inorder to validate their reason for buying a very expensive lens.

How I feel as well. The truth is Canon has been so successful on marketing some people actually worship anything 'L', the same way some worship anything '*'. But at least to the EF70-200/4L (IS or not), they are the ones that really stand out and well balanced imho.

ghelary · 12-17-2009, 04:04 AM

The equivalent of 70-200/4 on APSC is 60-250/4 in Pentax lineup, build and image IQ are comparable, but you have to keep in mind that the 70-200 is a 2.9x zoom and the 60-250 a 4.2x zoom. That quite make up for the price difference.

The equivalent of 70-200/4 on FF is 50-135/2.8 on Pentax (APSC)

Any cheaper lens on the Pentax lineup would be a deception as compared to the Canon L lens.

Now what you have to think about is if you were more using the long end of the 70-200 (then go for the 60-250) or the wide end (then go for the 50-135) The aperture / light condition / context of tacking pictures is also important.

The 60-250 has been made for outdoor shootings and has been optimised for the infinite.

The 50-135 has been optimised for portrait. Being one stop faster also help for shooting indoor / low dof.

Best regards,
Guillaume

photogerald · 12-21-2009, 07:27 PM

Originally posted by PentaxPoke

Are you both getting that from that article? Here is the main part of the conclusion:

"If you don't mind the lack of image stabilization, I'd recommend the Sigma, it is much cheaper than the Canon and it has better autofocus than the Tamron. Overall the Canon is the best, but it is way more expensive, so you have to evaluate if it is worth the price depending by your esigencies."

You also didn't read the link I attached regarding the Tamron sharpness at the edges, and AF slowness and inconsistency. Finally, you are comparing the wrong lens. The OP said he had the 70-200 f/4 not the 2.8. That is the specific lens I was talking about. They are different. "The sharpest zoom I ever used." -Ken Rockwell (Noted Nikonian)

I have used the 70-200 f/4 myself, and it was an eye-opening experience.

Oh well, this is a Pentax forum anyway, and we are getting off track...

I have no arguments with the accolades afforded to the 70-200/4L.

I just wanted to point out that one shouldn't make any conclusions about the Tamron's AF performance based on a review of a Canon mount model, as the Canon mount version uses an in-lens AF motor motor (and one of poor quality/performance apparently).

Owners of the Tamron in Pentax mount have reported that the AF is quite fast (although a little noisy, as is expected). That's not to say that it will match the AF performance of the Sigma HSM, but it is supposed to be much better than the Canon version.

PentaxPoke · 12-21-2009, 09:26 PM

Originally posted by photogerald

I have no arguments with the accolades afforded to the 70-200/4L.

I just wanted to point out that one shouldn't make any conclusions about the Tamron's AF performance based on a review of a Canon mount model, as the Canon mount version uses an in-lens AF motor motor (and one of poor quality/performance apparently).

Owners of the Tamron in Pentax mount have reported that the AF is quite fast (although a little noisy, as is expected). That's not to say that it will match the AF performance of the Sigma HSM, but it is supposed to be much better than the Canon version.

Interesting. If the Tamron is better than the EF 70-200 f/4 USM at AF then that must be some lens. I have experienced the EF 70-200 f/4 on a 7D recently, and it was the fastest, quietest autofocus I have ever experienced on any mount with any lens! Even when the focus ring was turned completely the opposite way, while in relative darkness. I even tried it down to a light level of EV 0 which is pretty darn dark, and it would accurately focus lock within a second. The 70-200 uses a full ring-USM motor. I wonder what is used on the Tamron version.

Chwisch87 · 12-21-2009, 10:33 PM

If the 70 to 200 is a Full Frame Measurement. The 50 to 135 Pentax would be the APS-C equivalent. I think.

PentaxPoke · 12-21-2009, 10:35 PM

Originally posted by Chwisch87

If the 70 to 200 is a Full Frame Measurement. The 50 to 135 Pentax would be the APS-C equivalent. I think.

The OP was using a 30D with a 70-200 f/4 and was looking for Pentax equivalent on a Pentax k-x. The 30D is not FF, therefore the closest Pentax equivalent is the 60-250, not the 50-135. You would be correct if the OP was using something like a 5D, or a 1D, and wanted a Pentax crop-frame equivalent to that.

bpjod · 12-21-2009, 11:45 PM

I've recently switched from Canon to Pentax for the small primes. I've acquired most of the DA Ltd. lenses. I love shooting with the DA70. That said, I miss my 70-200/4 and 400/5.6 but I don't want the bulk anymore. I'm trying the DA55-300 and for the most part I like it. It's got great image quality and the f/4 lasts to nearly 200mm (about 190mm).

On the other hand, I've been reading for a long time that Pentax's AF is slow, but I've never before experienced slow AF with my K7 and Ltd lenses as they're very fast. Now I have the 55-300 and I'm experiencing the slow AF that I've read about previously. There is no comparison in AF speed between the Canon 70-200/4 and the DA55-300. So far the range and size vs. the AF performance trade-off is acceptable to me but I might be tempted to try a DA*200/2.8 for sports photography if its AF speed is more like the DA Ltds.

photogerald · 12-21-2009, 11:54 PM

Originally posted by PentaxPoke

Interesting. If the Tamron is better than the EF 70-200 f/4 USM at AF then that must be some lens. I have experienced the EF 70-200 f/4 on a 7D recently, and it was the fastest, quietest autofocus I have ever experienced on any mount with any lens! Even when the focus ring was turned completely the opposite way, while in relative darkness. I even tried it down to a light level of EV 0 which is pretty darn dark, and it would accurately focus lock within a second. The 70-200 uses a full ring-USM motor. I wonder what is used on the Tamron version.

My reply was poorly-worded - what I meant was that the AF performance of the Tamron in Pentax mount beats the same lens in Canon mount, due to the poor in-lens AF motor used by Tamron in Canon mount. Sorry for the confusion.

Also, having used Canon in a previous life, I don't doubt the superior AF performance of the Canon 70-200/F4L.

12-17-2009, 12:27 AM	#32
PentaxPoke Veteran Member Join Date: Jan 2008 Location: Oklahoma Posts: 1,411	Originally posted by wallyb No joke, the Tamron is generally better in sharpness, not even factoring cost in. Even with "L" in the title, it's still made from the same elements as other lenses, and Tamron has been in the game for a very long time as well. Are you both getting that from that article? Here is the main part of the conclusion: "If you don't mind the lack of image stabilization, I'd recommend the Sigma, it is much cheaper than the Canon and it has better autofocus than the Tamron. Overall the Canon is the best, but it is way more expensive, so you have to evaluate if it is worth the price depending by your esigencies." You also didn't read the link I attached regarding the Tamron sharpness at the edges, and AF slowness and inconsistency. Finally, you are comparing the wrong lens. The OP said he had the 70-200 f/4 not the 2.8. That is the specific lens I was talking about. They are different. "The sharpest zoom I ever used." -Ken Rockwell (Noted Nikonian) I have used the 70-200 f/4 myself, and it was an eye-opening experience. Oh well, this is a Pentax forum anyway, and we are getting off track... Last edited by PentaxPoke; 12-17-2009 at 12:34 AM.

12-17-2009, 12:49 AM	#36
LeDave Veteran Member Join Date: Jun 2009 Location: Minneapolis - St. Paul Photos: Gallery Posts: 3,067	Originally posted by PentaxPoke I did read that one from LeDave, and I just quoted the conclusion from his link that said the Canon was the best! Also, I sent you a link to a site that has direct comparisons of both! You have to click the comparison. Here I did it for you: Canon EF 70-200mm f/4.0 L IS USM Lens - Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Comparison - ISO 12233 Resolution Chart Results Yeah but we were speaking of IQ here at first. But I see now you are moving onto more than just that for the favor of the Canon winning. Other than that what you did leave out was he stated the Canon was best after speaking of AF and build quality, only to conclude saying "actually, the Tamron is slightly sharper". So in terms of starting out what the argument was about, the Tamron does win out in IQ, but I do agree by it's "L" quality built lens, the Canon is better in it's own but at nearly twice the cost if IS is included. Last edited by LeDave; 12-17-2009 at 10:04 AM.

12-21-2009, 07:27 PM	#40
photogerald Senior Member Join Date: Sep 2009 Posts: 253	Can't compare in-lens AF with in-body Originally posted by PentaxPoke Are you both getting that from that article? Here is the main part of the conclusion: "If you don't mind the lack of image stabilization, I'd recommend the Sigma, it is much cheaper than the Canon and it has better autofocus than the Tamron. Overall the Canon is the best, but it is way more expensive, so you have to evaluate if it is worth the price depending by your esigencies." You also didn't read the link I attached regarding the Tamron sharpness at the edges, and AF slowness and inconsistency. Finally, you are comparing the wrong lens. The OP said he had the 70-200 f/4 not the 2.8. That is the specific lens I was talking about. They are different. "The sharpest zoom I ever used." -Ken Rockwell (Noted Nikonian) I have used the 70-200 f/4 myself, and it was an eye-opening experience. Oh well, this is a Pentax forum anyway, and we are getting off track... I have no arguments with the accolades afforded to the 70-200/4L. I just wanted to point out that one shouldn't make any conclusions about the Tamron's AF performance based on a review of a Canon mount model, as the Canon mount version uses an in-lens AF motor motor (and one of poor quality/performance apparently). Owners of the Tamron in Pentax mount have reported that the AF is quite fast (although a little noisy, as is expected). That's not to say that it will match the AF performance of the Sigma HSM, but it is supposed to be much better than the Canon version.

12-21-2009, 09:26 PM	#41
PentaxPoke Veteran Member Join Date: Jan 2008 Location: Oklahoma Posts: 1,411	Originally posted by photogerald I have no arguments with the accolades afforded to the 70-200/4L. I just wanted to point out that one shouldn't make any conclusions about the Tamron's AF performance based on a review of a Canon mount model, as the Canon mount version uses an in-lens AF motor motor (and one of poor quality/performance apparently). Owners of the Tamron in Pentax mount have reported that the AF is quite fast (although a little noisy, as is expected). That's not to say that it will match the AF performance of the Sigma HSM, but it is supposed to be much better than the Canon version. Interesting. If the Tamron is better than the EF 70-200 f/4 USM at AF then that must be some lens. I have experienced the EF 70-200 f/4 on a 7D recently, and it was the fastest, quietest autofocus I have ever experienced on any mount with any lens! Even when the focus ring was turned completely the opposite way, while in relative darkness. I even tried it down to a light level of EV 0 which is pretty darn dark, and it would accurately focus lock within a second. The 70-200 uses a full ring-USM motor. I wonder what is used on the Tamron version. Last edited by PentaxPoke; 12-21-2009 at 10:12 PM.

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12-17-2009, 12:20 AM	#31
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	Originally posted by frank2001 Hi all. I am an advanced amateur and have been for many many years. I've been a Canon DSLR user since the D30. I have wanted to downsize and made several unsuccessful attempts with Rebels, Olympus 4/3, Panasonic and Olympus micro 4/3 and my large hands just don't lend themselves well to those tiny grips and I miss the optical viewfinder. Also, I don't shoot nearly as much as I used to and have way too much money invested in my Canon stuff. I ordered a K-x today based on many opinions and reviews and the fact that it comes in White! I hope it's the answer. I've read the kit lens is pretty good so... First thing I'll need is a tele lens. I currently use a Canon 70-200mm f4 and haven't figured out the Pentax equivalent so any suggestions would be welcome Frank Hi Frank ! Welcome to Pentax Forums. If you are looking for something that is equivalent or better than the Canon 70-200 F4, I suggest that you get the Pentax Primes. I know they are not zooms but I could say they are the best of the bunch for Pentax. and also they are much faster than F4. the lens recommendations would be an FA31, FA77, and FA135/2.8 or better the K135/2.5. I believe you will be more than satisfied once you get to try this lens. mind you that I have tried those 3 lenses. 2 of which I can't afford right now and one which just I wasn't able to acquire due to an unfortunate incident.

12-17-2009, 12:33 AM	#33
wallyb Veteran Member Join Date: Nov 2008 Location: The Untied States Photos: Albums Posts: 1,881	Originally posted by PentaxPoke Are you both getting that from that article? Here is the main part of the conclusion: "If you don't mind the lack of image stabilization, I'd recommend the Sigma, it is much cheaper than the Canon and it has better autofocus than the Tamron. Overall the Canon is the best, but it is way more expensive, so you have to evaluate if it is worth the price depending by your esigencies." You also didn't read the link I attached regarding the Tamron. Finally, you are comparing the wrong lens. The OP said he had the 70-200 f/4 not the 2.8. That is the specific lens I was talking about. They are different. "The sharpest zoom I ever used." -Ken Rockwell (Noted Nikonian) Oh well, this is a Pentax forum anyway... You're asking me if I read links? Oof... I guess you didn't read the one posted in reply to you by LeDave: Juza Nature Photography Now, which site am I more inclined to believe... one with direct visual comparisons of four lenses side by side, or one without them... and with a canon camera on their front page... and the word "Canon" sprinkled out in every other link... and called "Canon Digital Lens Reviews"... And don't get me started on Ken Rockwell!

12-17-2009, 12:37 AM	#34
PentaxPoke Veteran Member Join Date: Jan 2008 Location: Oklahoma Posts: 1,411	Originally posted by wallyb You're asking me if I read links? Oof... I guess you didn't read the one posted in reply to you by LeDave: Juza Nature Photography Now, which site am I more inclined to believe... one with direct visual comparisons of four lenses side by side, or one without them... I did read that one from LeDave, and I just quoted the conclusion from his link that said the Canon was the best! Also, I sent you a link to a site that has direct comparisons of both! You have to click the comparison. Here I did it for you: Canon EF 70-200mm f/4.0 L IS USM Lens - Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Comparison - ISO 12233 Resolution Chart Results

12-17-2009, 12:41 AM	#35
wallyb Veteran Member Join Date: Nov 2008 Location: The Untied States Photos: Albums Posts: 1,881	Originally posted by PentaxPoke I did read that one from LeDave, and I just quoted the conclusion from his link that said the Canon was the best! Also, I sent you a link to a site that has direct comparisons of both! You have to click the comparison. Here I did it for you: Canon EF 70-200mm f/4.0 L IS USM Lens - Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Comparison - ISO 12233 Resolution Chart Results "but while the Canon and the Tamron are close (actually, the Tamron is slightly sharper)" From the Juza Nature Photography link. Maybe you missed that line? And again, I'm not sure what value there is in comparisons from a clearly Canon-sponsored, or at least Canon-biased, review site... Edit: and the center sharpness of the Tamron lens looks better in the link you gave me there... visually at least, though of course their review states otherwise. And I think anyone would expect a lens with a starting aperture of f/2.8 to perform worse on the corners than one that starts at f/4, even at the same aperture.

12-17-2009, 01:02 AM	#37
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	honestly speaking, the IQ of the "L" lenses can be matched by any maker. some are even slightly or a tad better than the "L" lenses when it comes to sharpness and rendering. what does make the "L" lenses stand out from the rest is it's build and AF function. that's it. let's face it. some people would tend to say that the IQ of the "L" lenses are unmatched inorder to validate their reason for buying a very expensive lens.

12-17-2009, 01:21 AM	#38
wlachan Veteran Member Join Date: Sep 2006 Location: Canada Photos: Albums Posts: 2,625	Originally posted by Pentaxor honestly speaking, the IQ of the "L" lenses can be matched by any maker. some are even slightly or a tad better than the "L" lenses when it comes to sharpness and rendering. what does make the "L" lenses stand out from the rest is it's build and AF function. that's it. let's face it. some people would tend to say that the IQ of the "L" lenses are unmatched inorder to validate their reason for buying a very expensive lens. How I feel as well. The truth is Canon has been so successful on marketing some people actually worship anything 'L', the same way some worship anything '*'. But at least to the EF70-200/4L (IS or not), they are the ones that really stand out and well balanced imho.

12-17-2009, 04:04 AM	#39
ghelary Veteran Member Join Date: Jul 2008 Location: Paris, France Photos: Gallery Posts: 613	The equivalent of 70-200/4 on APSC is 60-250/4 in Pentax lineup, build and image IQ are comparable, but you have to keep in mind that the 70-200 is a 2.9x zoom and the 60-250 a 4.2x zoom. That quite make up for the price difference. The equivalent of 70-200/4 on FF is 50-135/2.8 on Pentax (APSC) Any cheaper lens on the Pentax lineup would be a deception as compared to the Canon L lens. Now what you have to think about is if you were more using the long end of the 70-200 (then go for the 60-250) or the wide end (then go for the 50-135) The aperture / light condition / context of tacking pictures is also important. The 60-250 has been made for outdoor shootings and has been optimised for the infinite. The 50-135 has been optimised for portrait. Being one stop faster also help for shooting indoor / low dof. Best regards, Guillaume

12-21-2009, 10:33 PM	#42
Chwisch87 Veteran Member Join Date: Jan 2009 Location: Atlanta, GA Photos: Gallery Posts: 317	If the 70 to 200 is a Full Frame Measurement. The 50 to 135 Pentax would be the APS-C equivalent. I think.

12-21-2009, 10:35 PM	#43
PentaxPoke Veteran Member Join Date: Jan 2008 Location: Oklahoma Posts: 1,411	Originally posted by Chwisch87 If the 70 to 200 is a Full Frame Measurement. The 50 to 135 Pentax would be the APS-C equivalent. I think. The OP was using a 30D with a 70-200 f/4 and was looking for Pentax equivalent on a Pentax k-x. The 30D is not FF, therefore the closest Pentax equivalent is the 60-250, not the 50-135. You would be correct if the OP was using something like a 5D, or a 1D, and wanted a Pentax crop-frame equivalent to that.

12-21-2009, 11:45 PM	#44
bpjod Forum Member Join Date: Apr 2009 Location: Wetaskiwin, Alberta Posts: 85	I've recently switched from Canon to Pentax for the small primes. I've acquired most of the DA Ltd. lenses. I love shooting with the DA70. That said, I miss my 70-200/4 and 400/5.6 but I don't want the bulk anymore. I'm trying the DA55-300 and for the most part I like it. It's got great image quality and the f/4 lasts to nearly 200mm (about 190mm). On the other hand, I've been reading for a long time that Pentax's AF is slow, but I've never before experienced slow AF with my K7 and Ltd lenses as they're very fast. Now I have the 55-300 and I'm experiencing the slow AF that I've read about previously. There is no comparison in AF speed between the Canon 70-200/4 and the DA55-300. So far the range and size vs. the AF performance trade-off is acceptable to me but I might be tempted to try a DA*200/2.8 for sports photography if its AF speed is more like the DA Ltds.

12-21-2009, 11:54 PM	#45
photogerald Senior Member Join Date: Sep 2009 Posts: 253	Originally posted by PentaxPoke Interesting. If the Tamron is better than the EF 70-200 f/4 USM at AF then that must be some lens. I have experienced the EF 70-200 f/4 on a 7D recently, and it was the fastest, quietest autofocus I have ever experienced on any mount with any lens! Even when the focus ring was turned completely the opposite way, while in relative darkness. I even tried it down to a light level of EV 0 which is pretty darn dark, and it would accurately focus lock within a second. The 70-200 uses a full ring-USM motor. I wonder what is used on the Tamron version. My reply was poorly-worded - what I meant was that the AF performance of the Tamron in Pentax mount beats the same lens in Canon mount, due to the poor in-lens AF motor used by Tamron in Canon mount. Sorry for the confusion. Also, having used Canon in a previous life, I don't doubt the superior AF performance of the Canon 70-200/F4L.