New Tamron plastic fantastic primes

D1N0 · 10-30-2019, 05:25 AM

Originally posted by house

Same source. They are using the same housing and motor for all lenses to keep cost down.

Ok so it is a cost cutting decision. You get what you pay for or something. I would pick up the Samyang alternatives, which are cheaper, lighter and take 49mm filters.

normhead · 10-30-2019, 06:02 AM

Originally posted by house

The Tamron 35mm at f2.8 has better mtf than the dfa* 50mm at f4. Not saying it will be better before any reviews but initials are looking good.

Comparing different focal lengths is a poor practice.

house · 10-30-2019, 07:07 AM

Originally posted by normhead

Comparing different focal lengths is a poor practice.

Yes, but knowing that 50's are usually easier to make than 35's it's info that should make one take notice. Comparing f1.4 to f2.8 is also only sensible if you plan to shoot stopped down.

normhead · 10-30-2019, 07:31 AM

Originally posted by house

Yes, but knowing that 50's are usually easier to make than 35's it's info that should make one take notice. Comparing f1.4 to f2.8 is also only sensible if you plan to shoot stopped down.

I'm not aware that one is easier to make than the other. Perhaps you have link for that? The ideal FL for Pentax is 43mm. 50 is 7 over, 35mm is 8 under. Why would one be more difficult to make?

I've read magazine articles suggesting 35 is a standard lens, not wide angle.

In any case, the criteria for lens selection is not an MTF chart, it's "do I like the images." The big deal about the DFA 50 1.4 is there are some small areas where I prefer it's images to my DA*55 1.4. I"ve seen them, and I decided I'd be happy with the 55 and left over one. Is this 35 better? A better or similar MTF chart does not necessarily equate to a lens you like more.
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/302815-35mm-find-prime.html

Show me.

Last edited by normhead; 10-30-2019 at 07:43 AM.

house · 10-30-2019, 01:35 PM

Originally posted by normhead

In any case, the criteria for lens selection is not an MTF chart, it's "do I like the images."
Show me.

I'm guessing a Freudian typo above? s/the/my criteria?

Regardless you are funny character defending Pentax when there's nothing to defend. I explicitly said "I'm not saying its any better but initials are looking good"

normhead · 10-30-2019, 01:42 PM

You did mention the DFA 50 1.4, which is what I was objecting to.

The DFA 50 is a good lens. It's the heavy correction and smooth bokeh that make it exceptional. You can't see that in an MTF chart. Interesting you thought i was defending Pentax.

I thought I was pretty clear.

Quote:

A better or similar MTF chart does not necessarily equate to a lens you like more.

**luftfluss** · 10-30-2019, 02:14 PM

Originally posted by normhead

I'm not aware that one is easier to make than the other. Perhaps you have link for that? The ideal FL for Pentax is 43mm. 50 is 7 over, 35mm is 8 under. Why would one be more difficult to make?

Roger Cicala of Lensrentals has published his MTF measurements of various 24mm, 35mm, and 50mm lenses.

Lens Rentals | Blog

Lens Rentals | Blog

Lens Rentals | Blog

He does state, "As a general rule, the wider the lens, the more the MTF falls off away from center." The MTF data at Photodo (which is mostly for older lenses) also indicates that 50's generally have higher MTF's than wider lenses. From what I've read over the years, the necessity of a retrofocus design for wide angle lenses - kind of an inverted telephoto design - is a more difficult and delicate design than 50's and short teles.

normhead · 10-30-2019, 07:18 PM

Originally posted by luftfluss

Roger Cicala of Lensrentals has published his MTF measurements of various 24mm, 35mm, and 50mm lenses.

Lens Rentals | Blog

Lens Rentals | Blog

Lens Rentals | Blog

He does state, "As a general rule, the wider the lens, the more the MTF falls off away from center." The MTF data at Photodo (which is mostly for older lenses) also indicates that 50's generally have higher MTF's than wider lenses. From what I've read over the years, the necessity of a retrofocus design for wide angle lenses - kind of an inverted telephoto design - is a more difficult and delicate design than 50's and short teles.

That interesting... but somewhat dated. As general rule, means, not necessarily for a specific lens. but I get the concept.

mee · 10-30-2019, 08:16 PM

Originally posted by BigMackCam

I'll be surprised if Z and RF mount versions aren't offered soon enough... unless, of course, Nikon and Canon are somehow resisting / preventing third party development of lenses for their platforms. With Sigma officially covering L-mount, Tamron will want to capitalize on Z and RF...

Somehow?

Sony opened the E mount specs back in 2011. Plus there is no royalty fee.

Nikon and Canon have not done either and Z and R mounts are only around a year old each. So it will be awhile to see 3rd party autofocus lenses from them in number as they will have to be reversed engineered.

**BigMackCam** · 10-30-2019, 11:40 PM

Originally posted by mee

Somehow?

Sony opened the E mount specs back in 2011. Plus there is no royalty fee.

Nikon and Canon have not done either and Z and R mounts are only around a year old each. So it will be awhile to see 3rd party autofocus lenses from them in number as they will have to be reversed engineered.

Sure... I'm aware of that. What I meant was, if Nikon and Canon are somehow doing something with their lens communication protocol that makes it especially difficult to reverse engineer compared to their earlier F and EF mounts. If they're not, I've no doubt we'll see the Tamron lenses for Z and R mounts... Not for a little while, perhaps, but soon enough. I imagine Tamron is beavering away on the reverse engineering as we speak

Mistral75 · 10-31-2019, 02:53 AM

Originally posted by D1N0

Not very expensive but why 67mm filter threads for 2.8 lenses. Totally unnecessary

Tamron have used the same 67mm filter thread for all their lenses in Sony E mount so far.

D1N0 · 10-31-2019, 03:34 AM

Originally posted by Mistral75

Tamron have used the same 67mm filter thread for all their lenses in Sony E mount so far.

I think it is silly. They could have made nice pancakes instead of these oversized balloons.

house · 10-31-2019, 03:40 AM

Originally posted by D1N0

I think it is silly. They could have made nice pancakes instead of these oversized balloons.

They could also have made telephoto zooms or mirror lenses. They look OK sized. I like my tiny lenses but find that up to a certain size it doesn't matter. I do find lenses like the wr 55-80 kit a bit large for perma strapping.*

* I never use it because I don't like the optics but its also a bit big.

**luftfluss** · 10-31-2019, 07:25 AM

Originally posted by D1N0

I think it is silly. They could have made nice pancakes instead of these oversized balloons.

Dude, it's not like these lenses are huge. The are about the same size as the FA 31, and lighter.

Also, given the close-focus capability, while the lenses could be smaller, doubtful they could have been "pancakes".

D1N0 · 10-31-2019, 11:49 AM

Originally posted by luftfluss

Dude, it's not like these lenses are huge. The are about the same size as the FA 31, and lighter.

Also, given the close-focus capability, while the lenses could be smaller, doubtful they could have been "pancakes".

So now I am a dude. Well one that is entitled to an opinion without being duded. <insert appropriate insult here>!

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10-30-2019, 05:25 AM	#31
D1N0 Pentaxian Join Date: May 2012 Location: --- Photos: Gallery Posts: 6,802	Originally posted by house Same source. They are using the same housing and motor for all lenses to keep cost down. Ok so it is a cost cutting decision. You get what you pay for or something. I would pick up the Samyang alternatives, which are cheaper, lighter and take 49mm filters.

10-30-2019, 06:02 AM	#32
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by house The Tamron 35mm at f2.8 has better mtf than the dfa* 50mm at f4. Not saying it will be better before any reviews but initials are looking good. Comparing different focal lengths is a poor practice.

10-30-2019, 07:07 AM	#33
house Pentaxian Join Date: May 2015 Photos: Albums Posts: 3,306 Original Poster	Originally posted by normhead Comparing different focal lengths is a poor practice. Yes, but knowing that 50's are usually easier to make than 35's it's info that should make one take notice. Comparing f1.4 to f2.8 is also only sensible if you plan to shoot stopped down.

10-30-2019, 07:31 AM	#34
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by house Yes, but knowing that 50's are usually easier to make than 35's it's info that should make one take notice. Comparing f1.4 to f2.8 is also only sensible if you plan to shoot stopped down. I'm not aware that one is easier to make than the other. Perhaps you have link for that? The ideal FL for Pentax is 43mm. 50 is 7 over, 35mm is 8 under. Why would one be more difficult to make? I've read magazine articles suggesting 35 is a standard lens, not wide angle. In any case, the criteria for lens selection is not an MTF chart, it's "do I like the images." The big deal about the DFA 50 1.4 is there are some small areas where I prefer it's images to my DA55 1.4. I"ve seen them, and I decided I'd be happy with the 55 and left over one. Is this 35 better? A better or similar MTF chart does not necessarily equate to a lens you like more. https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/302815-35mm-find-prime.html Show me. Last edited by normhead; 10-30-2019 at 07:43 AM.*

10-30-2019, 01:35 PM	#35
house Pentaxian Join Date: May 2015 Photos: Albums Posts: 3,306 Original Poster	Originally posted by normhead In any case, the criteria for lens selection is not an MTF chart, it's "do I like the images." Show me. I'm guessing a Freudian typo above? s/the/my criteria? Regardless you are funny character defending Pentax when there's nothing to defend. I explicitly said "I'm not saying its any better but initials are looking good"

10-30-2019, 01:42 PM	#36
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	You did mention the DFA 50 1.4, which is what I was objecting to. The DFA 50 is a good lens. It's the heavy correction and smooth bokeh that make it exceptional. You can't see that in an MTF chart. Interesting you thought i was defending Pentax. I thought I was pretty clear. Quote: A better or similar MTF chart does not necessarily equate to a lens you like more.

10-30-2019, 02:14 PM	#37
luftfluss Site Supporter Join Date: Jun 2011 Location: NJ Photos: Gallery \| Albums Posts: 11,619	Originally posted by normhead I'm not aware that one is easier to make than the other. Perhaps you have link for that? The ideal FL for Pentax is 43mm. 50 is 7 over, 35mm is 8 under. Why would one be more difficult to make? Roger Cicala of Lensrentals has published his MTF measurements of various 24mm, 35mm, and 50mm lenses. Lens Rentals \| Blog Lens Rentals \| Blog Lens Rentals \| Blog He does state, "As a general rule, the wider the lens, the more the MTF falls off away from center." The MTF data at Photodo (which is mostly for older lenses) also indicates that 50's generally have higher MTF's than wider lenses. From what I've read over the years, the necessity of a retrofocus design for wide angle lenses - kind of an inverted telephoto design - is a more difficult and delicate design than 50's and short teles.

10-30-2019, 07:18 PM	#38
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by luftfluss Roger Cicala of Lensrentals has published his MTF measurements of various 24mm, 35mm, and 50mm lenses. Lens Rentals \| Blog Lens Rentals \| Blog Lens Rentals \| Blog He does state, "As a general rule, the wider the lens, the more the MTF falls off away from center." The MTF data at Photodo (which is mostly for older lenses) also indicates that 50's generally have higher MTF's than wider lenses. From what I've read over the years, the necessity of a retrofocus design for wide angle lenses - kind of an inverted telephoto design - is a more difficult and delicate design than 50's and short teles. That interesting... but somewhat dated. As general rule, means, not necessarily for a specific lens. but I get the concept.

10-30-2019, 08:16 PM	#39
mee Veteran Member Join Date: May 2010 Posts: 7,403	Originally posted by BigMackCam I'll be surprised if Z and RF mount versions aren't offered soon enough... unless, of course, Nikon and Canon are somehow resisting / preventing third party development of lenses for their platforms. With Sigma officially covering L-mount, Tamron will want to capitalize on Z and RF... Somehow? Sony opened the E mount specs back in 2011. Plus there is no royalty fee. Nikon and Canon have not done either and Z and R mounts are only around a year old each. So it will be awhile to see 3rd party autofocus lenses from them in number as they will have to be reversed engineered.

10-30-2019, 11:40 PM	#40
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,670	Originally posted by mee Somehow? Sony opened the E mount specs back in 2011. Plus there is no royalty fee. Nikon and Canon have not done either and Z and R mounts are only around a year old each. So it will be awhile to see 3rd party autofocus lenses from them in number as they will have to be reversed engineered. Sure... I'm aware of that. What I meant was, if Nikon and Canon are somehow doing something with their lens communication protocol that makes it especially difficult to reverse engineer compared to their earlier F and EF mounts. If they're not, I've no doubt we'll see the Tamron lenses for Z and R mounts... Not for a little while, perhaps, but soon enough. I imagine Tamron is beavering away on the reverse engineering as we speak

10-31-2019, 02:53 AM	#41
Mistral75 Pentaxian Join Date: Feb 2009 Location: Paris, France Posts: 7,527	Originally posted by D1N0 Not very expensive but why 67mm filter threads for 2.8 lenses. Totally unnecessary Tamron have used the same 67mm filter thread for all their lenses in Sony E mount so far.

10-31-2019, 03:34 AM	#42
D1N0 Pentaxian Join Date: May 2012 Location: --- Photos: Gallery Posts: 6,802	Originally posted by Mistral75 Tamron have used the same 67mm filter thread for all their lenses in Sony E mount so far. I think it is silly. They could have made nice pancakes instead of these oversized balloons.

10-31-2019, 03:40 AM	#43
house Pentaxian Join Date: May 2015 Photos: Albums Posts: 3,306 Original Poster	Originally posted by D1N0 I think it is silly. They could have made nice pancakes instead of these oversized balloons. They could also have made telephoto zooms or mirror lenses. They look OK sized. I like my tiny lenses but find that up to a certain size it doesn't matter. I do find lenses like the wr 55-80 kit a bit large for perma strapping.* * I never use it because I don't like the optics but its also a bit big.

10-31-2019, 07:25 AM	#44
luftfluss Site Supporter Join Date: Jun 2011 Location: NJ Photos: Gallery \| Albums Posts: 11,619	Originally posted by D1N0 I think it is silly. They could have made nice pancakes instead of these oversized balloons. Dude, it's not like these lenses are huge. The are about the same size as the FA 31, and lighter. Also, given the close-focus capability, while the lenses could be smaller, doubtful they could have been "pancakes".

10-31-2019, 11:49 AM	#45
D1N0 Pentaxian Join Date: May 2012 Location: --- Photos: Gallery Posts: 6,802	Originally posted by luftfluss Dude, it's not like these lenses are huge. The are about the same size as the FA 31, and lighter. Also, given the close-focus capability, while the lenses could be smaller, doubtful they could have been "pancakes". So now I am a dude. Well one that is entitled to an opinion without being duded. <insert appropriate insult here>!