ProfHankD

ProfHankD

Lives in United States Lexington, United States
Works as a Professor
Has a website at http://aggregate.org/hankd/
Joined on Mar 27, 2008
About me:

Plan: to change the way people think about and use cameras by taking advantage of cameras as computing systems; engineering camera systems to provide new abilities and improved quality.

Comments

Total: 338, showing: 41 – 60
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In reply to:

peevee1: The 9mm body cap has 5 elements in 4 groups vs 3 elements in 3 groups for 15mm body cap. Plus being a fish-eye, they have put no effort into barrel distortion correction. :)
I guess it should make it much better optically than 15mm BCL. If it would only be weather-sealed and have electronic contacts for automatic setting of FL and EXIF, it would be a great addition to the lens lineup.

5 elements for f/8 fisheye lens! Wow.

I missed that. 140 is probably close enough for the GoPro crowd. I don't get much more than that out of my ancient Spiratone 12mm fisheye, which is also f/8 (or f/11 or f/16), on APS-C, and it's still quite appealing -- as opposed to pseudo-fisheye adapters giving a distorted view of as little as 75 degrees. However, 140 is not going to be taken seriously for things like 360-degree stitching.

Direct link | Posted on Jan 31, 2014 at 10:51 UTC
In reply to:

peevee1: And yet - nobody cared. ;-)

Really? I'd expect realtors to be going nuts over this....

Direct link | Posted on Jan 30, 2014 at 11:41 UTC
On Sony a7R teardown! Roger Cicala gets his hands dirty news story (136 comments in total)

The number of different types of screws is a pretty good indication of how many independently-designed subsystems are being stuck together. Despite the A7/A7R seeming like they were pushed out the door a bit quickly, it is impressive to see that Sony coordinated the design, engineering, and manufacturing processes so tightly.

It is worth noting, however, that Cicala's conclusion that the A7R is cheaper to make than a DSLR is probably only half right. It looks like Sony invested the money up-front on design and engineering of new subsystems so production cost is low, whereas most DSLRs try to moderate costs by sticking-together existing subsystems that are cheap due to long-term volume production. The real difference is that this is why Sony gets to innovate without a huge cost penalty.

Direct link | Posted on Jan 30, 2014 at 11:32 UTC as 54th comment | 1 reply
On Olympus announces Stylus SP-100 superzoom with dot-sight news story (89 comments in total)
In reply to:

Gordon W: No RAW, no deal!

These days, most cameras that don't have raw have serious lens issues being corrected in software... so raw isn't as good a deal as you'd think. That said, I can get better images (and a significantly wider view) out of an A4000 using CHDK to extract raws from it... they just look nasty without a lot of careful postprocessing. ;-)

Direct link | Posted on Jan 29, 2014 at 19:27 UTC
In reply to:

peevee1: The 9mm body cap has 5 elements in 4 groups vs 3 elements in 3 groups for 15mm body cap. Plus being a fish-eye, they have put no effort into barrel distortion correction. :)
I guess it should make it much better optically than 15mm BCL. If it would only be weather-sealed and have electronic contacts for automatic setting of FL and EXIF, it would be a great addition to the lens lineup.

5 elements for f/8 fisheye lens! Wow.

I also think the cheap and tiny "rectangular fisheye" is the interesting lens here, provided the IQ is reasonable and it really is a roughly 180-degree fisheye (not just a badly barrel-distorted moderately wide view). The fixed f/8 aperture is fine; it's ok for low light at such a short focal length, and it is probably near the diffraction limit so stopping-down further wouldn't be good anyway.

Incidentally, the video crowd may see this as a reason not to have to switch to a GoPro for some things, so it's probably got a market even if it just barely looks good at 1080 resolution.

Direct link | Posted on Jan 29, 2014 at 15:18 UTC
On Fujifilm X-T1 First Impressions Review preview (1657 comments in total)

In almost every way, very similar to the Sony A7. However, the A7 is 24MP FF for about $300 more. That's a pretty small price bump from the X-T1's 16MP APS-C.

Direct link | Posted on Jan 28, 2014 at 13:17 UTC as 352nd comment | 11 replies
On Using third-party lenses on Sony Cyber-shot a7 / a7R article (469 comments in total)
In reply to:

Rick Knepper: I am visiting here only because I saw the article at Sony Rumors criticizing DPR's conclusions. Without reading SR or DPR's article, I already have a strong opinion about adapted lenses based on my experience over the years adapting many other brands' lenses to my Canon cameras. The OEM alignments for camera/lens combos have to be precise and it's a miracle that copy variation isn't a bigger problem than it is but introducing an adapter (3rd party or OEM) has to increase the incidence of copy variation even more.

I long ago divested most of my alternative lenses to be done with adapters.

I will not be interested in the A7r until a full range of native lenses become available and field results made known.

OT: I will probably wait until Sony produces a longer lasting battery.

Actually, the constraints of modern autofocus (low moving mass and friction) mean that they are poorly aligned compared to typical old manual lenses on adapters -- and I've measured this on my 130+ lenses. It's mostly element decentering on modern lenses, whereas adapters can only cause a very slight positioning error for the entire optical unit. Worst case for adapted lenses is typically a very slight tilt, which only impacts performance on an optical test bed in which you don't slightly angle the camera or target to match the slightly tilted focus plane.

Direct link | Posted on Jan 27, 2014 at 14:53 UTC
On Phase One announces IQ250 50MP CMOS medium format back news story (197 comments in total)

Very nice. However, why does their photo show a 16x9 aspect image on the live view when the sensor is 4x3 aspect?

Direct link | Posted on Jan 25, 2014 at 15:03 UTC as 10th comment | 1 reply
On Sony Alpha 7 Review preview (1594 comments in total)
In reply to:

ProfHankD: Rated lowest of the full-frame cameras? I have an A7 that I'm using for very technical work and I can't agree. Aside from any IQ arguments, I think the EVF alone should justify gold, as would the fact that it can use just about any lens ever made.

However, DPReview did catch my biggest gripe: the 1/60s A mode preference. Basically, all Sony models have followed the 1/focal_length rule, but they have a long tradition of assuming unknown lenses are 50mm, hence selecting 1/60s. Allowing the user to manually set the minimum speed would be a step in the right direction, but the real fix is to let the user tell the camera about the unchipped lenses and maintain a list of such lens data to select from instead of the "shoot without lens" choice. That lens info should go into the EXIF and be used to compute 1/focal_length, or perhaps even allow a user-specified default slowest shutter speed to be registered for each lens.

My "technical work" involves computational photography research which is, to say the least, very unforgiving about IQ issues.

None of the competing FF cameras DPReview ranked higher than the A7 has anything like that EVF, and I do indeed think it is a qualitative improvement over the best OVF -- particularly in allowing you to see focus and DoF, which autofocus DSLR OVFs sacrifice in order to make the view brighter (installing a 3rd-party focus screen helps somewhat). DSLRs also have the issue that PDAF can't work stopped down -- which you need to see DoF; without manual focus aids in the OVF, you simply don't have much of an option.

Direct link | Posted on Jan 24, 2014 at 00:04 UTC
On Sony Alpha 7 Review preview (1594 comments in total)
In reply to:

DT200: There are so many here that create a fantasy word in order to justify their favorite brand camera. When fans start claiming the A7 sensor has higher IQ than the D600 when DxO proves the opposite, you can clearly see this. One guy even claimed the A7 has better handling, better controls, higher IQ, better native lenses than the D600 which really has me scratching my head. And now suddenly no one ever uses JPEGs.
As I said before the D600 almost everything better than the A7 (especially the important things like focusing, speed, IQ, more/better auto focusing lenses, etc.). The D600 has hundreds of more legacy lenses that it can use AND auto focus with, and once you add and adapter to the A7 the size difference is reduced.

E-mount cameras can autofocus not only native E-mount, but also all A-mounts (very fast), all Canon EF/EF-S, and all Contax G. That's way more AUTOFOCUS lenses than any other camera ever made. Nothing wrong with the D600, but it's not the "game changer" that the A7 is.

Direct link | Posted on Jan 23, 2014 at 14:15 UTC
On Sony Alpha 7 Review preview (1594 comments in total)

Rated lowest of the full-frame cameras? I have an A7 that I'm using for very technical work and I can't agree. Aside from any IQ arguments, I think the EVF alone should justify gold, as would the fact that it can use just about any lens ever made.

However, DPReview did catch my biggest gripe: the 1/60s A mode preference. Basically, all Sony models have followed the 1/focal_length rule, but they have a long tradition of assuming unknown lenses are 50mm, hence selecting 1/60s. Allowing the user to manually set the minimum speed would be a step in the right direction, but the real fix is to let the user tell the camera about the unchipped lenses and maintain a list of such lens data to select from instead of the "shoot without lens" choice. That lens info should go into the EXIF and be used to compute 1/focal_length, or perhaps even allow a user-specified default slowest shutter speed to be registered for each lens.

Direct link | Posted on Jan 23, 2014 at 13:58 UTC as 232nd comment | 3 replies
On Using third-party lenses on Sony Cyber-shot a7 / a7R article (469 comments in total)
In reply to:

Cameracist: The author is right - none of the lenses are worth spending thousands to shoot them with the smeary edges uncropped:-) I mean, I really love my old manual lenses, it's fun using them, but until the price of affordable mirrorles fullframe cameras drop to hundreds, I will stay with film cameras for fun and APS-C (with a split screen!) for digital capture.

Take a look at my Dec 29, 2013 article: http://www.dpreview.com/articles/5881382628/old-slr-lenses-full-frame-focal-reducer-or-aps-c
Wide open, a lot of lenses do better on APS-C + focal reducer than on FF, but usually because of vignetting, not blurry corners, being cropped out. Arguably, the poor man's choice would now be an A3000 + Lens Turbo behind old glass: under $500 total.

That said, the A7 does a touch better than my NEX-7 + LT with most FF lenses stopped down to optimal apertures.

Also, the 17mm and 57mm lenses in Barney's article do pretty badly compared to most of my (under $30 average) 130+ old lenses. The 17mm isn't a surprise -- old ultrawides are technologically challenged. The 57mm is unexpectedly much worse wide open than my Canon FL 55mm f/1.2, so I wonder about lens condition ($30 is very low for this lens). However, a lot of $30 lenses are worthy of a NEX-7/A7/A7R behind them, especially when used at optimal apertures.

Direct link | Posted on Jan 22, 2014 at 13:27 UTC
On Using third-party lenses on Sony Cyber-shot a7 / a7R article (469 comments in total)
In reply to:

ProfHankD: I've been using Sonys with old lenses since the A350 (with a 3rd-party focus screen), but peaking is way better. I've found it very effective with my 130+ old lenses on the NEX-5, NEX-7, and A7. There is a trick, however:

Set the peaking to "high." With good lighting and a good lens, lots will be peaked. Train yourself to ESTIMATE THE PRECISE FOCUS DEPTH WITHIN THE DEPTH RANGE SHOWING PEAKING. The precise focus point is a little closer than the average depth peaked -- it's rather like reading a slide rule. It takes a little practice, but this method is very fast and far more accurate than using peaking directly as an indication of focus quality because high-contrast scene elements slightly out of focus will peak more than low-contrast ones in focus.

The (signed, indicating before/after the focus point) diameter of an out-of-focus spot at distance d is c1-c2/d where c1, c2 are constants determined by the lens and current focus point. Peaking stops when the unsigned spot size exceeds a specific value. This means the exact ratio is lens and focus dependent, but you're really interpolating a 1/x function. That sounds technical, but you don't need to think of it numerically.

If you practice with a particular lens estimating & confirming using magnified view at typical focus distances, you can quickly and easily learn the ratio for that lens. You don't really think about a ratio, you just develop a feel for how much in front of the midpoint focus is. It is always somewhat closer than the average distance, and any reasonable guess will give much more accurate focus than simply assuming that the entire peaked region is in focus.

Note that high peaking also makes it easy to judge DoF.

Direct link | Posted on Jan 22, 2014 at 05:05 UTC
On Using third-party lenses on Sony Cyber-shot a7 / a7R article (469 comments in total)

As for the poor choice of longest shutter speed in "A" mode:

The lack of a method to tell a Sony body about the manual (unchipped) lens mounted prevents the camera from knowing the focal length and automatically setting a reasonable longest shutter speed for A mode. There also isn't a manual way to set it. This is a dumb problem from day 1 with the NEX-5 and I don't know why Sony hasn't fixed with a firmware update. There are a variety of ugly workarounds using S or M mode, but none is ideal.

However, the multi-shot modes work fine with manual lenses, and can significantly reduce both camera and subject motion blur in many cases where slow shutter speeds are used for JPEG capture. The obvious choice is "anti-motion blur" mode, but all the multi-shot modes seem to do intelligent alignment and merging that helps reduce blur somewhat.

Direct link | Posted on Jan 21, 2014 at 22:29 UTC as 139th comment
On Using third-party lenses on Sony Cyber-shot a7 / a7R article (469 comments in total)

I've been using Sonys with old lenses since the A350 (with a 3rd-party focus screen), but peaking is way better. I've found it very effective with my 130+ old lenses on the NEX-5, NEX-7, and A7. There is a trick, however:

Set the peaking to "high." With good lighting and a good lens, lots will be peaked. Train yourself to ESTIMATE THE PRECISE FOCUS DEPTH WITHIN THE DEPTH RANGE SHOWING PEAKING. The precise focus point is a little closer than the average depth peaked -- it's rather like reading a slide rule. It takes a little practice, but this method is very fast and far more accurate than using peaking directly as an indication of focus quality because high-contrast scene elements slightly out of focus will peak more than low-contrast ones in focus.

Direct link | Posted on Jan 21, 2014 at 22:25 UTC as 140th comment | 2 replies
On Fujifilm teases upcoming SLR-style X system camera news story (921 comments in total)
In reply to:

jhinkey: I don't get all the "retro" comments. Almost every digital camera in production today has some form of previous film camera design component to it. Why is that? - Because the ergonomics worked. Middle placed hump for the EVF allows for good hand-holding with longer/heavier glass and is better for left-eyed folks.
Top control dials allow quick assessment of basics important settings and adjustments w/o having to hold down two buttons or dive into a menu - this works for some, perhaps not for others though. Heck, even a left-side placed EVF (like my GX7) is a throw back to rangefinder designs and some find it better for shooting for their particular way.
Who cares if it's a "retro" design as long as the ergonomics work well and the all-important innards are top knotch in performance!

There are issues associated with retro concepts like perforating the body skin with lots of mechanical control dials with calibrated markings. Most of these "features" were dropped for cost, reliability, and functionality reasons. Relative performance of mechanical and electronic systems by these metrics have changed a lot over the years. Cost and reliability issues are obvious. An example of a functionality issue is that a calibrated shutter speed dial probably will not let you set 1/640s, while an electronic shutter and controls trivially can.

In sum, you're paying for most of those retro things in a variety of ways. Many of us don't see the value.

Direct link | Posted on Jan 20, 2014 at 17:39 UTC
On Fujifilm teases upcoming SLR-style X system camera news story (921 comments in total)

Another very retro-looking camera (about the same vintage look as Nikon's Df) and, from rumors elsewhere, also 16MP, but APS-C and not low priced. 16MP is plenty to surpass people's IQ expectations from film cameras, so I think that lowish sensel count with potentially better high ISOs makes sense.

It is sad that it might take cameras like this to convince folks that mirrorless is ok for serious work -- people still don't get it. Last week at a camera club meeting somebody pointed at my A7 and said something to the effect that it was cool that micro4/3 sensors were enabling cameras to be that small -- but of course the A7 is a full frame mirrorless. In summary, FujiFilm (even their name is retro!) is doing a good service to the community here in helping to wean people off DSLRs, and I'll bet they get a following and some profit out of it too. I'll stick with my "less retro" and better price/performance A7 and NEX-7 for now....

Direct link | Posted on Jan 20, 2014 at 16:17 UTC as 150th comment
On CES 2014 Nikon Stand Report news story (66 comments in total)

I like the array of 68 DSLRs. Well, I'd like it if my computational photography research budget let me buy things like 68 DSLRs. I just have fleets of webcams and Canon PowerShots under CHDK. ;-)

Incidentally, I'm really impressed if they got reliable wireless tethering on the show floor at CES. I would have expected enough wireless traffic to cause all sorts of problems -- as we've had doing even more modest wireless capture control at IEEE/ACM Supercomputing conferences.

Direct link | Posted on Jan 8, 2014 at 23:14 UTC as 4th comment
On Samsung launches daul-grip, 60x WB2200F superzoom with Wi-Fi news story (203 comments in total)

This sure is a killer bridge camera. 20-1200mm view in a camera that looks like what people think a high-end camera should look like.

Don't know what they use the space in the bottom grip for... does it take AA batteries? Actually, I use a lot of cameras tethered and this could be pretty wonderful for that.. now we just have to get them to put a motor-driven tripod mount in the base so it can do pan/tilt via remote....

Direct link | Posted on Jan 7, 2014 at 19:48 UTC as 73rd comment
On Samsung NX30 First Impressions Review preview (353 comments in total)
In reply to:

ProfHankD: Once again, Samsung has made a mutant Sony that in many ways is nicer. Basically, this is a Sony A3000++. Ok, the sensor probably isn't quite as good (although DxOMark shows Samsung isn't far behind the A3000), but Samsung actually makes pretty much everything in their cameras, and they're getting better at everything. They've got a long way to go to match an A7R, but I'll keep watching them....

Honestly, the only thing that's kept me from buying a Samsung camera is the slightly long flange distance and relatively poor availability of legacy lens adapters (e.g., no Lens Turbo) for NX. Then again, I own a Galaxy S3, so I guess I actually do own two Samsung cameras.... ;-)

Yes, NX is short enough for many things, but adapters are rarer and pricier, and there are not any focal reducers -- which is the primary way to compete with full-frame (see http://www.dpreview.com/articles/5881382628/old-slr-lenses-full-frame-focal-reducer-or-aps-c ). I also happen to have some Minolta/Sony A-mount autofocus lenses, which are impressively fast to AF on my LA-EA2 and LA-EA4 thanks to the SLT mirror and PD sensor in those adapters.

Direct link | Posted on Jan 5, 2014 at 13:37 UTC
Total: 338, showing: 41 – 60
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