Erik Magnuson

Erik Magnuson

Lives in United States Cape Canaveral, FL, United States
Has a website at http://www.pbase.com/maderik
Joined on Dec 29, 2000
About me:

This is what I'd like to appear on my public 'posters (sic)
profile.'

Comments

Total: 218, showing: 61 – 80
« First‹ Previous23456Next ›Last »
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

Photo Pete: Anyone know why this is seen as a 'breakthrough' when the Nikon 1 series has been doing on-sensor pdaf for a couple of years AND with very high continuous AF rates?

Groucher: brilliant with the FT-1 for "pdaf for a couple of years AND with very high continuous AF rates"? The AF-C support w/FT-1 is only a few months old, not years. Does it continue to change focus with the FT-1 at high rates?

Posted on Oct 11, 2013 at 19:42 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

Lucas_: I wonder why DPR is taking all this trouble in explaining how to use the Canon 70D AF effectively... I don't remember them doing this when the Sony SLTs ( which have continuous LV AF on both LCD and VF ) came out!
Talk about bias...

And DPR dedicated a page about this feature in the A99 review, so there is no bias.

Posted on Oct 11, 2013 at 18:41 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

ManuelVilardeMacedo: It is ridiculous that some blame the test for the poor OVF AF results!
As for me, Canon can include their 'dual pixel' autofocus system among its least of Most Relevant Innovations. People should congratulate the ones who developed this technology, as it's definitely an advance for photography.
...Still it puzzles me to see manual focus works even better than 'dual pixel'. One would be forgiven to ask why they bothered inventing autofocus at all.

3. The lens age also matters - the newest Canon lenses have improvements that can be used to increase PDAF accuracy:
http://www.lensrentals.com/blog/2012/07/autofocus-reality-part-ii-1-vs-2-and-old-vs-new

It's not clear how much the 70D can utilize these capabilities.

Posted on Oct 11, 2013 at 17:52 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

Photo Pete: Anyone know why this is seen as a 'breakthrough' when the Nikon 1 series has been doing on-sensor pdaf for a couple of years AND with very high continuous AF rates?

Because it can do it with existing lenses that were not designed with a new small/light internal focusing mechanism. How well does the Nikon 1 do with the FT-1 adapter and AF-S lenses?

Posted on Oct 11, 2013 at 17:46 UTC
On Preview:canon-eos-70d (1333 comments in total)

BTW, OVF phase detect autofocus *can be* as accurate as CDAF - but it takes improvements to BOTH the lens mechanics AND the camera sensor/algorithms. See the charts from http://www.lensrentals.com/blog/2012/07/autofocus-reality-part-ii-1-vs-2-and-old-vs-new where the 5DIII with the new 24mm f/2.8 IS has the *same accuracy/consistency in either mode*. Yet the old 24mm f/2.8 lens on the 5DIII does not. Neither does the new lens on the 5DII. The entire "Autofocus reality" series is worth a read.

Posted on Oct 11, 2013 at 17:19 UTC as 76th comment | 3 replies
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

Bob Meyer: So wait. Did DPR NOT do the micro-focus adjustment BEFORE running these tests? That's what is sounds like, and if so then the entire test is invalid.

It sounds like they tested a known mis-adjusted system for the standard PDAF test. That's like putting the wrong size tires on your car and then complaining that the speedometer is inaccurate.

Every rim+tire combination has to be individually microadjusted (i.e. balanced) for best performance. DPR just plopped the tires on without that step and then complained about the ride.

Posted on Oct 11, 2013 at 16:06 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

Cane: Is there an English translation of this?

If critical autofocus matters, either use the live-view autofocus OR calibrate your camera for each lens. If subject tracking in continuous shooting matters you must use the regular AF on a 70D.

Posted on Oct 11, 2013 at 15:34 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

Lucas_: I wonder why DPR is taking all this trouble in explaining how to use the Canon 70D AF effectively... I don't remember them doing this when the Sony SLTs ( which have continuous LV AF on both LCD and VF ) came out!
Talk about bias...

Sony SLTs use the same set of independent PDAF sensors for autofocus regardless of the viewfinder so there is nothing different to test (that's what the translucent mirror is for - to direct light to the PDAF sensors). Their PDAF system will be subject to the same types of variability as the 70D OVF PDAF and so they also have microadjustment options to compensate.

Posted on Oct 11, 2013 at 15:24 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

crackshooter: First time poster, first time DSLR-buyer so it is kind of safe to call me a noob..
I have a question regarding the micro-adjustment of the 70D's AF: -Does the prosedure need to be repeated each time a lens is changed for another/removed, or does the camera remember the tweak for individual lenses?

You can either enter a global adjustment for all lenses or a per lens adjustment for up to 40 lenses. For zooms, you can adjust wide and tele separately.

Posted on Oct 11, 2013 at 15:20 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

ijustloveshooting: what a lame that Conventional, OVF autofocus screws all the time...then what's the point of a dslr?

Because it's about getting good shots under a wide variety of lenses+conditions and not just static high-contrast targets at short distances on a tripod.

Posted on Oct 11, 2013 at 14:45 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

groucher: The Autofocus review page shows a serious problem with the OVF focussing capabilities of this camera but the studio comparisons do not reproduce the problem. What's going on - is this yet another contrived 'fault' or is this Canon's justification for their new tech? Either way, I'm not impressed.

Studio comparisons use manual focus unless the camera only has AF. Conventional PDAF accuracy/reliability depends on BOTH the camera AND lens, so any results would not apply to your camera+lens anyway.

Posted on Oct 11, 2013 at 14:35 UTC
On Preview:canon-eos-70d (1333 comments in total)
In reply to:

Joe Mayer: I would appreciate it if Canon would spend more time improving the accuracy and consistency of my AF through my viewfinder. Live view autofocus is not an option for the type of shooting I do. I'm not against this new technology, just attached to viewing my subject through the viewfinder. Please do whatever it takes, even if it means making the viewfinder electronic. In the meantime, I'll continue afma-ing my lenses and though it greatly improves the performance of all my lenses, I'd not begrudge no longer having to perform this sometimes tedious procedure.

Canon has improved conventional PDAF accuracy and consistency. But it requires changes to both bodies and lenses and so you won't get it with the 85mm f/1.8. See
http://www.lensrentals.com/blog/2012/08/autofocus-reality-part-3b-canon-cameras

Posted on Oct 11, 2013 at 14:17 UTC
On Olympus PEN E-P5 Review preview (494 comments in total)

DPR: "In a way, this isn't entirely the camera's fault ..."

What an odd statement. Does this mean it's the user's fault? Or that perhaps it's an "act of God"?

DPR: "... it's not some kind of mechanical malfunction that actively causes blurring"

Continuing oddity: Does this mean DPR thinks the blurring is from "passive" causes? Or that it's working as designed and so not a malfunction?

It's certainly the camera's fault and it's certainly a design flaw. It may be either significant or insignificant depending on workarounds and type of shooting. Some additional shots showing what the visible difference is when using the rear LCD or a tripod would have been more useful than these odd statements which appear intended more to palliate brand zealots than refine the issue.

Direct link | Posted on Oct 4, 2013 at 16:20 UTC as 118th comment | 2 replies
On Olympus OM-D E-M1 Review preview (2142 comments in total)
In reply to:

mpgxsvcd: Let me sum up what every poster wants to say.

1. A full frame sensor is bigger than an m4/3s sensor and offers shallower depth of field.

2. F2.8 is F2.8 on any system. All cameras will yield the same shutter speed for a given ISO and focal ratio.

3. 4/3s and especially m4/3s lenses are smaller and lighter than APS-C and Full Frame lenses.

4. The EM-1 focuses very fast and accurately with m4/3s lenses. Not so much with 4/3s lenses.

5. EM-1 video is a disappointing 1080p @ 30 FPS at 24Mbps. No true 60p recording. Not even in 720p.

6. The E-M1 has live view Bulb time with refresh rates of several minutes or more.

7. The Flash synch speed is an excellent 1/320 of a second which could mean that rolling shutter is reduced.

8. The class leading Olympus 5 axis IS works in stills and movie mode.

10. There is no built-in flash on the EM-1 because they believe everyone who buys it will just use an external flash.

11. They will never make another true 4/3s camera or 4/3s lens again.

Flash sync speed (mechanical shutter timing) has nothing to do with rolling shutter (sensor shutter timing.)

Direct link | Posted on Sep 10, 2013 at 20:08 UTC
On Olympus OM-D E-M1 Review preview (2142 comments in total)
In reply to:

chris96326: Focus Peaking (apparently m4/3 lenses only??)
Better Grip and button spacing
Phase Focus (apparently legacy 4/3 lenses only)
More buttons (but in a different arrangement, why?)
Keeping the tilt screen -- no lousy swivel, selfies are for amatuers

Looks like a market winner and a great evolution camera on paper. Sample images on this sight are nothing to write home about. I will sit this one out and wait for the GX-7 to ship.

I am more interested in the new lens to compete with Panny's 12-35mm.

The PDAF is used with u4/3 lenses for continuous AF focus tracking.

Direct link | Posted on Sep 10, 2013 at 14:52 UTC
On Olympus OM-D E-M1 Review preview (2142 comments in total)
In reply to:

Harry S: As a motorsport shooter the continuous AF has me very interested, a big expensive leap to pre-order without a good idea of how in practice it will work for fast moving subjects though.

"if you're a Four Thirds lens owner and you're expecting full DSLR performance, you're going to be disappointed" doesn't sound like very good to me. If it can't do single focus fast with old 4/3 lenses, tracking AF is not going to be magically better.

Direct link | Posted on Sep 10, 2013 at 13:42 UTC
On Did Sigma design the Olympus M.Zuiko 75mm F1.8? article (200 comments in total)
In reply to:

jhinkey: It's one thing to design the optics, another completely to design the mechanical and electrical components and figure out how to get it manufactured to the price point and quality level that is desired.

Sigma has likely had the capability to design excellent optics for years, but the mechanical/electrical design & manufacturing may be on Oly's side of things.

I think a lot of companies are capable of stellar optical designs, but getting them to be made small enough, cheap enough, reliable enough can be a skill that perhaps only a few have.

Um, you do know what Sigma's main business is - making lenses. It's just as likely Sigma designed all of optics/mechanics/electronics -- they are a member of the consortium. Sigma might even manufacture this lens for Olympus (all Sigma lenses are made in Japan.) This is not the first OEM u4/3 prime that Sigma has been rumored to have done.

Direct link | Posted on Aug 29, 2013 at 17:59 UTC
On Sony A3000 preview (681 comments in total)
In reply to:

zodiacfml: Hey Sony, can you do a NEX 3 with this cheap EVF?

Because he wants the NEX6 form-factor at a NEX3 price?

Direct link | Posted on Aug 28, 2013 at 18:52 UTC
In reply to:

Jon Stern: Re: 3) the current design of the EFS-1 was extremely difficult to produce. Specifically, it took hundreds of engineering hours to produce one unit with a success rate of about one unit in three working;

We were hand-building the prototypes without the final mass production tooling and it was slow (I don't know where hundred of engineering hours comes from!) and we had a low yield. This was of concern to me, but mostly from the perspective of MP schedule and ramp.

Anyone who has been involved in real mass production knows that assembly cycle time and yield go through a steep, early learning curve. There were no fundamental issues with our assembly process, which was a lot simpler than DSLRs of the time.

The "hundred of hours" is a quote from the lawsuit. But just ask Microsoft about early Xbox ramp up and yield issues.

Direct link | Posted on Aug 21, 2013 at 00:41 UTC

Possibly the most technical write up:
http://www.edn.com/design/sensors/4338303/Electronic-film-focuses-on-low-power-high-image-quality

Major limitations included other than those already discussed.
- could not use a shutter speed slower than 1/15th It doesn't mention if there were limits on sequential shooting.
- used sound of mirror up for activation - could not be used for RF cameras and not reliable with manual wind noise.
- could not use DX coding - some cameras assume DX read means advance film when back closed.

If SF had been able to ship, would they have survived? The tricky part would have been how well it would have worked in customer hands (I.e. defect and return rate) and surviving the cash-flow killer of the Osboune effect (I,e., who will buy the current product if its known a supposedly better one was on the way.)

Direct link | Posted on Aug 21, 2013 at 00:19 UTC as 35th comment
Total: 218, showing: 61 – 80
« First‹ Previous23456Next ›Last »