Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-27-2017, 07:55 PM   #16
Pentaxian
Site Supporter
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 28,915
QuoteOriginally posted by Paul the Sunman Quote
For what it's worth, about 13% of my shots with the DFA* 70-200 are below f/4. Of those, about half are at 200mm, 15% are at 70mm, and the rest are evenly spread across the range. The lens is superb wide open, so there is never any reason to avoid f/2.8 other than for depth of field requirements.
Unfortunately that's the kind of information we compile after we buy the lens. Of my 8200 images currently on my drive, 500 are wider than ƒ4. That is 6%. My 2.8 primes include the 35 2.4, 40XS 2.8, 50 1.7, 50 macro 2.8, Sigma 70 macro 2.8, Tamron 90 macro 2.8. DA*200 2.8 and Tamron SP AF 300 2.8300 2.8. I have lots of opportunity to shoot under ƒ4, I just don't do it much. My philosophy has always been "Cover everything with slow zooms, then fill in your preferred focal lengths with fast prime." That definitely keeps the weight down on your walks.

But ultimately, what you buy depends on what you shoot. Unfortunately if you don't have everything covered, what you buy is also also determines what you shoot. You won't shoot a lot of 2.8 images, you you don't have any 2.8 lenses.It's a conundrum.

06-27-2017, 08:56 PM   #17
Veteran Member




Join Date: Nov 2014
Location: Edmonton
Posts: 542
don't forget that an f2.8 lens is likely to outperform an f4 lens at f4.


that's sort of the whole point. if a large number of your shots are at f4 or similar, an f2.8 lens will give you better results.


just because you CAN shoot wide open doesn't mean that the best photos will be realized at that aperture.

i wouldn't suggest that using a 70-200 f2.8 at f4 most of the time is wasting the lens.
06-28-2017, 05:41 AM   #18
Pentaxian
Site Supporter
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 28,915
QuoteOriginally posted by wibbly Quote
don't forget that an f2.8 lens is likely to outperform an f4 lens at f4.
Do you mean apart from more light for the AF system? Do you mean many ƒ4 and greater lenses are consumer lenses, not manufactured to the same technical standard?. Which performance are you talking about?

I know you're not talking about lenses of the same quality with the FA 200 ƒ4 macro being pretty much top of the heap in terms of performance, over all those 2.8 lenses.

I suspect you are equating ƒ4 with cheaper glass and manufacturing. There's actually quite a lot of ƒ4 high end glass as well across all the brands.

Last edited by normhead; 06-28-2017 at 05:52 AM.
06-28-2017, 07:59 AM   #19
Veteran Member




Join Date: Nov 2014
Location: Edmonton
Posts: 542
no. i'm equating it to almost all lenses increasing in performance when stopped down over wide open.

an f2.8 lens stopped down to 4 is likely going to perform better than an f4 lens wide open.

similarly an f1.4 lens at f2 is quite likely to outperform an f2 lens at f2.

plus you get the brighter viewfinder which is always nice.

06-28-2017, 08:15 AM   #20
Pentaxian
Site Supporter
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 28,915
OK where exactly does that come from?

A DA*200 stopped down to 4 is not better than an FA*200 macro. although i expect that will be close.

The DA*200 stopped down to ƒ4, 2026.5 lw/ph.


DA*60-250 wide open at ƒ4 and 299mm 2018 lw/ph


These lenses are virtually identical at 200mm despite one being a zoom and one being a prime, one opening to ƒ2.8 and one opening to ƒ4. By ƒ5.6 and ƒ8 the 60-250 is noticeably better even though it's an ƒ4 lens. Maybe you have an example of what you are discussing.

SO far I'm one for one in the discussing the two lenses I own. Personally I see no need to go further. But if you can come up with a couple examples.... I might consider the possibility you are on to something. Current evidence suggests otherwise. YOu have to check, lens by lens which is better. The generalization you propose is probably going to be wrong as much as it's right and therefore of no real value.

Last edited by normhead; 06-28-2017 at 08:30 AM.
06-28-2017, 08:48 AM   #21
Veteran Member




Join Date: Nov 2014
Location: Edmonton
Posts: 542
the fa*200 macro is a choice you made because of its known out of this world sharpness. generally comparing a macro lens to a non isn't going to give you a fair playing field in the realm of sharpness.

would you put the 35 limited macro against a 35 2.4? probably not.


i don't have the same overlap in my system that you do so i can't give you any examples based on my gear, and i'm not about to compare a 31ltd to a 16-50 at 31 because that defeats the purpose.


maybe someone can compare an fa50 1.4 at f2 vs an a50 f2 at f2. i looked for examples but couldn't find any
06-28-2017, 02:53 PM   #22
Pentaxian
Site Supporter
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 28,915
QuoteOriginally posted by wibbly Quote
the fa*200 macro is a choice you made because of its known out of this world sharpness. generally comparing a macro lens to a non isn't going to give you a fair playing field in the realm of sharpness.

would you put the 35 limited macro against a 35 2.4? probably not.


i don't have the same overlap in my system that you do so i can't give you any examples based on my gear, and i'm not about to compare a 31ltd to a 16-50 at 31 because that defeats the purpose.


maybe someone can compare an fa50 1.4 at f2 vs an a50 f2 at f2. i looked for examples but couldn't find any
So, why are you so sure you are right about this?

Just random, looking for lenses of the same focal length.






The 1.4 is better at ƒ2.8 and 4, but worse at ƒ5.6. And the 1.4 is comparatively awful at ƒ1.4. I still don't see any evidence a 1.4 lens is sharper at F4 as a rule. I think you're confusing the fact that lenses are generally sharper stopped down to ƒ5.6 with thinking if you started at ƒ5.6 and stopped down you'd get a sharper image, because every lens in your mind is better stop down. Fast 1.4 lenses are better than themselves stopped down, not necessarily better than an ƒ4 lens or an ƒ5.6 lens wide open at the same ƒ-stop.

Different lenses have different characteristics.

Last edited by normhead; 06-28-2017 at 03:08 PM.
06-28-2017, 04:26 PM   #23
Pentaxian




Join Date: Dec 2010
Location: Ontario
Photos: Gallery
Posts: 2,871
QuoteOriginally posted by wibbly Quote
maybe someone can compare an fa50 1.4 at f2 vs an a50 f2 at f2. i looked for examples but couldn't find any
I can get close, below is an FA50/1.4 at f/2 compared to an M50/2 at f/2 (entire photo for reference on the left, crops in the middle and right, camera k5iis). I hadn't done a side-by-side before, but it confirmed what I already had figured from practical use - I have little reason to use the M50 unless I plan to physically bash it into things (it's build is solid). But the drawbacks of a faster lens here are, in absolute terms, minor. The FA50 is a $200 lens and weighs 220g (so already affordable and small), the M50/2 was $20 (with a k1000 attached) and 160g.

Try not to take this too seriously. It's just crops of the central bit as I would want to spend more time aligning the focal plane before comparing the corners, and I mostly did it as I saw the (extremely relevant to this thread) Olympus ad on the back of a stack of Popular Photography magazines sitting on my shelf. Consider the equipment shown in the ad and ask yourself if you would you buy a 2000mm f/2.8 lens if you were just going to shoot it at f/4? Or never put a TC on it? Seems silly, you could probably save $140k and a few hundred kg by sticking with the more affordable and portable 2000mm f/4. It also saves on jeep damage.



06-28-2017, 05:10 PM   #24
Veteran Member




Join Date: Nov 2014
Location: Edmonton
Posts: 542
QuoteOriginally posted by normhead Quote
So, why are you so sure you are right about this?

Just random, looking for lenses of the same focal length.






The 1.4 is better at 2.8 and 4, but worse at 5.6. And the 1.4 is comparatively awful at 1.4. I still don't see any evidence a 1.4 lens is sharper at F4 as a rule. I think you're confusing the fact that lenses are generally sharper stopped down to 5.6 with thinking if you started at 5.6 and stopped down you'd get a sharper image, because every lens in your mind is better stop down. Fast 1.4 lenses are better than themselves stopped down, not necessarily better than an 4 lens or an 5.6 lens wide open at the same -stop.

Different lenses have different characteristics.

Your data agrees with my statement. Generally a lens wide open won't perform as well as one that isn't.


Of course factors like cost come in to play but generalizations are that way because they are exactly that.


The only point I was making is that buying a lens at f2.8 and using it at f4 isn't wasting the lens as you hinted at in your first post.
06-28-2017, 07:13 PM   #25
Veteran Member




Join Date: Dec 2016
Posts: 522
Original Poster
Yes thanks for all the feedback the 70-200 likely will get my money before 2017 ends.
07-06-2017, 09:59 AM   #26
Pentaxian
Site Supporter
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 28,915
QuoteOriginally posted by wibbly Quote
The only point I was making is that buying a lens at f2.8 and using it at f4 isn't wasting the lens as you hinted at in your first post.
No but it is carrying extra weight and spending extra money, and no the data doesn't support your statement. The data supports the statement that you have to go lens by lens. Assuming that the 1.4 lens is better than the ƒ4 lens at ƒ4 is a crap shoot as often wrong as it is right. If you really care about lens quality and IQ why would you even entertain such a notion?
07-06-2017, 11:04 AM   #27
Resident fiddler
Loyal Site Supporter
LensBeginner's Avatar

Join Date: Sep 2014
Photos: Albums
Posts: 4,382
QuoteOriginally posted by gm4life Quote
I am largely free of LBA...
QuoteOriginally posted by gm4life Quote
But I am down for the new DFA 85 * when released but am seriously considering another "fast" telephoto zoom for my kit sometime for the KP and K3II.
Tsk, tsk...
07-06-2017, 06:39 PM   #28
Pentaxian




Join Date: Dec 2016
Posts: 941
@gm4life: The D-FA 70-200mm f/2.8 and DA* 60-250mm f/4 are very fine lenses. So is the DA* 50-135mm and provides better range at the wider end. Quite some time ago I went for the DA* 50-135mm f/2.8 and I have been delighted with its fine IQ. It is the equivalent to having the D-FA 70-200mm f/2.8 on the K-1 at a fraction of the size and weight. I considered the DA* 60-250 f/4, but I value the f/2.8 since I do a lot of low light shooting, and the weight of the DA* 50-135mm is much lighter. It handles really well on the KP, and factors into the unique design philosophy of the KP- exceptional pro-style build and performance in a lighter, comparatively compact package. The DA 20-40mm f/2.8-4 as you know, balances beautifully on the KP, and is very light. The DA* 50-135mm is a terrific matchup, at only 5" and 1.5 lb for a tele zoom lens of f/2.8

For a great KP zoom lens trekking kit, I have the DA 20-40 on camera put into a mid-large size camera belt holster, using the strap cross-shoulders plus the belt loop for stability. Into the front accessory pocket I zip up my DA 15mm Ltd with a patch of bubble wrap padding inside the pocket front. Into a lens belt holster on my other side I have the DA* 50-135mm. If I switch lenses, the camera holster size I selected will just barely still zip up with the DA* 50-135mm installed. This setup works for me very well, and it is mostly WR.

I figure with only a little crop I can get a 200mm framing anyway, but if I'm doing a lot out at that range, I could snap on my DA* 200mm f/2.8, or even my FA* 300mm f/4.5. This way I never have to deal with handling a 3 or 4 lb lens.



If I should decide to get a K-1, it will be primarily for putting some of my fine FF wide-angle to mid FL lenses back to use in their original FOV. For tele work, with the quality IQ now capable with APS-C, I'll simply stick with it for tele work, due to size/weight/cost advantages.

Last edited by mikesbike; 07-06-2017 at 07:00 PM.
07-12-2017, 10:22 AM   #29
Pentaxian




Join Date: Jul 2011
Posts: 1,160
QuoteOriginally posted by gm4life Quote
So I am very much enjoying my current Pentax gear. I am largely free of LBA... But I am down for the new DFA 85 * when released but am seriously considering another "fast" telephoto zoom for my kit sometime for the KP and K3II.

I have...
DA HD 15 Limited
DA HD 16-85
DA HD 20-40 Limited
DA HD 35 Limited Macro
DA SMC 50
DA SMC 55 *
DA HD 55-300 (screw drive)
DA SMC 300 *

I am considering the 70-200 HD DFA *, 50-135 SMC DA * and the 60-250 SMC DA *. Obviously budget isn't a big issue more of a consideration of what makes sense my gut says go 70-200 but the range of the 60-250 is tempting. I thought about the 200 SMC DA * but double the price gets me a 2.8 from 70-200.

Thoughts suggestions? Is the 70-200 just massive for a K3II or a KP with large grip (battery grip on both of course)?
If you consider FF an option, go for D-FA* 70-200. It performs great on Pentax APS-C bodies and is ready for FF. It is heavy and expensive, but worth the price.
Otherwise the 60-250 is still a very nice option with more zoom. The 70-200 will be by far your biggest lens! Go and try 70-200 vs 60-250 w.r.t. size and weight.

Knowing where the comparison graphs come from, some people compare apples to bananas. Photozone tested the DA200 with a 10MP camera. Maybe the camera was the limiting factor not the lens in that test. Same for 60-250. KP and K3ii have a couple more pixel to be resolved!
08-26-2017, 09:48 PM   #30
Veteran Member




Join Date: Dec 2016
Posts: 522
Original Poster
Thanks everyone for the thoughts I am going down the 70-200 FF ready route. My two most expensive lenses will be designed for FF or FF compatible in the case of the DA 300 *.

I am going to wait for a good sale to take the plunge! I know they run in 200 bucks off sometimes and will jump on it then.

Two questions...

1. Does it fit in the supplied bag/case with the tripod foot on it?

2. What kind of strap to hook into the tripod mount so I can put it around my neck from the lens instead of the camera... Any suggestions for set-ups and brands?
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
canon, da, da*, da*200, depth, dfa, dfa*, f/4, ff, field, grip, hd, k-mount, k3ii, kp, lens, pentax, pentax lens, plan, portraits, range, size, slr lens, smc, sports, weight
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Question Names appearing with ampersand and bold - does it do anything, and how do I do it? pathdoc Site Suggestions and Help 15 03-24-2016 06:12 PM
Full Frame Telephoto Compared to APS-C Telephoto Capture C_Jones Pentax SLR Lens Discussion 21 05-03-2015 07:09 AM
Next Next Pentax. Now MJB DIGITAL Photographic Technique 16 02-12-2008 07:00 PM
Lets talk about the next-next Pentax codiac2600 Pentax News and Rumors 63 01-14-2008 08:01 PM



All times are GMT -7. The time now is 11:59 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top