Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-23-2015, 08:58 AM   #136
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,576
QuoteOriginally posted by philbaum Quote
With K-mount, they wouldnt' have been able to keep them on the shelves.
That is so true. Tamron, pls be reading this.

06-23-2015, 12:56 PM   #137
Site Supporter




Join Date: Feb 2011
Posts: 4,892
No joke. Pentax doesn't need all three 150-600-ish lenses (Tamron, Sigma, Sigma) but two would be nice.

I'm sure the Pentax will be nice too but a 600mm is still better than 450...
06-23-2015, 02:54 PM   #138
Pentaxian
philbaum's Avatar

Join Date: Oct 2007
Location: Port Townsend, Washington State, USA
Posts: 3,659
QuoteOriginally posted by jsherman999 Quote
Welcome to the squeeze. A few of us described this current situation starting about 3-4 years ago, if I recall.
.
I do recall you saying that - many times

1. As to the original OP question, lets say that one buys one of the Sony FE F4 zooms that they have for a A7X model. This FF combination provides no more light exposure over my K3 + F2.8 aps zoom. But doesn't the FF camera provide additional SNR and Dynamic range benefits over the above mentioned Pentax APS combo?? I don't see this mentioned to much, but there are still benefits to be had. Plus, faster primes would really benefit the FF camera.

2. There are at least 2 ways of converting to FF, a full conversion or a supplemental/partial conversion. What i'm thinking of doing is keeping my K3 and the key lenses i frequently use with it, sell the remainder, and then buy a Sony FF and a very few lenses to do the specific low light work i have in mind. Thats a lot less money than a full conversion.
06-24-2015, 01:02 AM   #139
Pentaxian
Fogel70's Avatar

Join Date: Sep 2009
Location: Stockholm, Sweden
Photos: Albums
Posts: 1,737
QuoteOriginally posted by philbaum Quote
I do recall you saying that - many times

1. As to the original OP question, lets say that one buys one of the Sony FE F4 zooms that they have for a A7X model. This FF combination provides no more light exposure over my K3 + F2.8 aps zoom. But doesn't the FF camera provide additional SNR and Dynamic range benefits over the above mentioned Pentax APS combo?? I don't see this mentioned to much, but there are still benefits to be had. Plus, faster primes would really benefit the FF camera.
As long as you can use base ISO on both cameras, the FF will give some advantage, but on the other hand noise and DR do not differ much at base ISO between FF and APS-C.
When you need to use one stop higher ISO on FF to compensate for the slower lens or when you need to use one stop higher ISO stopping down the lens one extra stop on FF to get the DOF, you will not see much difference in noise or DR between FF and APS-C.

Comparing Sony A7II with K3, A7II has a 0.2 stop advantage on DR at base ISO (according to DXOMark). So far Sony does not seems to make full use of the FF-advantage when it comes to DR and noise.
FI Nikon seem to do much better on this, but on the other hand both Nikon 750 and 7200 have about one stop DR advantage at base ISO over Sony A7II and Pentax K3. So FF does not seems to have a general advantage in DR over APS-C at base ISO.

Attached Images
   
06-24-2015, 02:33 AM   #140
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,931
QuoteOriginally posted by philbaum Quote
I do recall you saying that - many times

1. As to the original OP question, lets say that one buys one of the Sony FE F4 zooms that they have for a A7X model. This FF combination provides no more light exposure over my K3 + F2.8 aps zoom. But doesn't the FF camera provide additional SNR and Dynamic range benefits over the above mentioned Pentax APS combo?? I don't see this mentioned to much, but there are still benefits to be had. Plus, faster primes would really benefit the FF camera.

2. There are at least 2 ways of converting to FF, a full conversion or a supplemental/partial conversion. What i'm thinking of doing is keeping my K3 and the key lenses i frequently use with it, sell the remainder, and then buy a Sony FF and a very few lenses to do the specific low light work i have in mind. Thats a lot less money than a full conversion.
If you are shooting at f4 on full frame and f2.8 on APS-C, you would have to bump your iso on full frame by one stop meaning that your dynamic range and SNR would be pretty similar between your crop and full frame shots. The benefit comes if you are able to shoot with a faster lens on your full frame camera.
06-24-2015, 07:34 AM   #141
Pentaxian
Wired's Avatar

Join Date: Aug 2009
Location: Edmonton, AB
Photos: Gallery | Albums
Posts: 2,494
getting rid of the math and all the technical mumbo jumbo... you only need an FF if it is the right too for the job you are doing at that time. In fact, even then I would argue that an APSC format camera can do everything a 35mm format can do if all other specs are equal. There is a learning curve going from APSC to 35mm. It will not instantly over night make you a better photographer, in fact it will make you a worse photographer the day you pick it up. You need to shoot differently when you pickup a 35mm camera. For me personally, if every spec was the same aside from sensor size, knowing what I know now, I would purchase the crop sensor camera. The exception would be things that are matched to sensor size, like view finder size and high-iso noise.

I've been shooting without my D800 since mid-May (as it's in the shop....again) and I have only missed shooting with it for two specific things... flash sync/hss speed with my studio lights and AF motor speed (more a system concern). If Pentax were to release a mkii version of the DA* lenses with updated focus motors that are as fast as Nikon's 24-70 and 70-200...I may be tempted to ditch the Nikon. I can work around the flash system limitations.
06-24-2015, 08:15 AM   #142
Pentaxian
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 23,717
QuoteOriginally posted by ElJamoquio Quote
No joke. Pentax doesn't need all three 150-600-ish lenses (Tamron, Sigma, Sigma) but two would be nice.

I'm sure the Pentax will be nice too but a 600mm is still better than 450...
Stick a 1.4 TC on it.... now it's a 210-630.
06-25-2015, 10:23 AM   #143
Site Supporter
markku55's Avatar

Join Date: Dec 2011
Location: Hanko, Finland
Posts: 195
QuoteOriginally posted by normhead Quote
Stick a 1.4 TC on it.... now it's a 210-630.

And if the FF do have enough off resolution, the easyest way to get "longer" lens is to crop the picture.

06-25-2015, 06:01 PM   #144
Pentaxian
philbaum's Avatar

Join Date: Oct 2007
Location: Port Townsend, Washington State, USA
Posts: 3,659
QuoteOriginally posted by Fogel70 Quote
As long as you can use base ISO on both cameras, the FF will give some advantage, but on the other hand noise and DR do not differ much at base ISO between FF and APS-C.
When you need to use one stop higher ISO on FF to compensate for the slower lens or when you need to use one stop higher ISO stopping down the lens one extra stop on FF to get the DOF, you will not see much difference in noise or DR between FF and APS-C.

Comparing Sony A7II with K3, A7II has a 0.2 stop advantage on DR at base ISO (according to DXOMark). So far Sony does not seems to make full use of the FF-advantage when it comes to DR and noise.
FI Nikon seem to do much better on this, but on the other hand both Nikon 750 and 7200 have about one stop DR advantage at base ISO over Sony A7II and Pentax K3. So FF does not seems to have a general advantage in DR over APS-C at base ISO.
Good point. Another loose screw in these comparisons is Pentax being straight about the ISO numbers. while Canikon and Sony all seem to be playing games with these ISO calculations, which creates an unfavorable impression of Pentax.

The SNR chart below compares K3, D810 and A7II. Its remarkable how close D810 and A7II are in these charts. For the same corrected iso, K3 is about 5% below D810/A711 at 100 iso, but that increases to about 9% when one looks at these values at 800 iso. So getting at higher iso's, the SNR becomes more and more favorable to the full frames. That sort of makes sense because the larger sensor area becomes key in capturing more photons when they are getting to be few in number. Nikon D750, not included, is a later generation of sensor and clearly outclasses D810, A711. The K3 sensor is now at least 30 months old - i'm not sure if its the same as the one installed in K3 II.

As you pointed out, if the FF is at F4 and the aps camera is at F2.8, the SNR value becomes almost identical (because the ISO is increased to provide equal exposure conditions)

[IMG][/IMG]

Last edited by philbaum; 06-25-2015 at 06:06 PM.
06-27-2015, 11:10 AM   #145
Site Supporter




Join Date: Feb 2011
Posts: 4,892
QuoteOriginally posted by normhead Quote
Stick a 1.4 TC on it.... now it's a 210-630.
It's a rare zoom where the (zoom + TC) does better than (zoom + cropping). Some of the better 70-200 f/2.8's do better with a TC IMO. I have no experience with the 150-450 with a TC but I'd guess it's not much of an improvement over cropping in practice (which for me is handheld and wide open for a lens like that).

If you're taking pictures in mid-day sunlight on a tripod your experience might be quite different.

Personally I'm glad Pentax is (rumored to be) using the 42MP FF sensor. It makes it easier to forgo the TC and crop.
06-27-2015, 03:01 PM   #146
Pentaxian
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 23,717
You'd be wrong if that was your guess. The 150-450 does quite well with the TC. Actually with anything but a kit lens type of lens you will do much better with a TC. Pentax has said with he 1.4 TC on a good lens the loss of resolution is 3.% and since the increase due to enlargement is 40% that's a 37% gain on your subject using the TC. MY A-400 which was a consumer lens, not an A* benefits from the 1.4 TC but doesn't do well with the 1.7 AF adapter. That gives me a pretty clear line as to how much enlargement a consumer lens will handle. Any DA* and all but the worst DAs will be improved over cropping the same lens.
06-27-2015, 03:23 PM   #147
Site Supporter
mwilky55's Avatar

Join Date: Feb 2012
Location: Southeastern Connecticut
Photos: Albums
Posts: 603
QuoteOriginally posted by Flylooper Quote
Interesting colloquy here.

Amateur photography, like any hobby, is an industry. My other hobbies happen to be golf and fly fishing. The financial health of all three are dependent on new players, of course; but most of all on a constant turnover of equipment among the folks already engaged in the hobby. Pick up any trade magazine on fly fishing or golf and all the ads promise a longer cast, or better line performance on the water—or, in golf, a longer straighter drive, pitch or chip with this newer, better, set of clubs. And so it is with cameras and lenses, I think.

The fact is that the fish don't give a rip whether I'm using a 800 dollar rod or a 150 dollar rod, and my casting technique is good but certainly not of championship calibre—and a more expensive rod, though nice to have, is not necessary in order to have a good day on the water.

If they built me a custom made set of golf clubs, they wouldn't straighten out my lifelong slice at the tee box or lengthen my drives (or pitches, or chips) commensurate with the cost of the clubs.

Speaking only for myself, the only honest reason I would buy a FF camera is (a) I have money to burn and (b) the satisfaction of knowing I have "the best" of something. Probably the same reasons I would choose a Mercedes over a VW or a Buick.

Omestes, I looked at your pix on 500px. Let me tell you: You're doing just great with that crappy old APS-C sensor.

Just sayin'...
Flylooper and Omestes, thank you both for the wise and thought provoking sanity check.
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!
24x36mm, announcement, beer, camera, computer, ff, fish, full-frame, fun, gear, ii, images, k-3, k3ii, k5, lenses, lightroom, pentax, pixel, resolution, ricoh, rod, rods, scene, tool, upgrade
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax-F 35-70mm worth the upgrade? nyonya Pentax K-30 & K-50 29 09-06-2014 09:15 PM
Is it worth the upgrade from the A 50 f/1.7 to f/1.4? Fat Albert Pentax SLR Lens Discussion 27 03-14-2014 03:31 AM
K30 Firmware upgrade - Is it worth buying a 32gb card? Steven Chain Pentax K-30 & K-50 7 02-11-2013 04:56 PM
Is it worth trying to fix a kr or upgrade? Kricket Pentax K-r 13 07-15-2011 10:29 PM
k10D Is an upgrade worth it? emptydam Pentax DSLR Discussion 10 11-11-2007 04:18 PM



All times are GMT -7. The time now is 02:04 PM. | See also: NikonForums.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