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Messages - Mika

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Lenses / Re: EF lens design shrunk to EF-M specs
« on: January 07, 2015, 02:14:39 PM »
Generally speaking, optics tend to work fine with downscaling. In the case of EF-M, yes that would indeed be possible. But the question is, does it make sense to do that? Occasionally, downscaling from full-frame's 43.2 mm image diagonal to 21.6 mm diagonal makes aberration correction (astigmatism and coma) easier by roughly a factor of four.

This tends to allow a reduction in the number of components in the objective, thus reduction in the price. So a designer might find himself in a situation that he can take away one lens from the formula without affecting anything much, or with only small performance degradations. Without a very good reason, this is often the case that happens.

For example, take a look at Sigma's 30/1.4 Art (DC=APS-C) and at Sigma's 35 50/1.4 Art (DG=FF) where the number of lenses is noticeably less in the 30 mm version. This did come with a slight compromise on the lens performance, though.

Does this answer your question?

EDIT: Oh, forgot to mention that upscaling an optical design doesn't work as nicely as typically the optical aberrations increase at least quadratically, so the general rule is down-scaling is OK, up-scaling isn't.

EDIT^2: Mika isn't paying attention today. Of course it should say 30/1.4 Art and 50/1.4 Art as we are talking about comparable FOV with scaling...

One of the most successful trip combos I've had is 5D, 28/1.8 and 85/1.8. It allows pretty good portability, and will fit to a small camera bag, while still allowing some wide and some mild framing from further distances.

If I'd be visiting cities in Central Europe and think about doing mostly photography there, I'd take 28/1.8 only with a full-frame. Hopefully Canon improves this lens at some point though, but at F/8 you're pretty much golden. The possibility of getting that aperture at this point of the year remains debatable, possibly in Barcelona, but I don't know about Germany... From your line-up, EF 16-35 IS or EF-M 22/2.0 should work fine.

Interestingly enough, I do have some L lenses, but I don't prefer to take them abroad. The non-L objectives are much more light-weight AND don't cause a lot of grief if they get damaged or broken. The L lenses I use here.

I haven't found a lot of use for telephotos in European cities, though there's always one photo you think you could have taken with that massive telephoto, but then again, that usually means you'd need to lug it around and lose a dozen of others due to mobility restrictions.

Third Party Manufacturers / Re: Have you repaired your 50 Art?
« on: December 31, 2014, 07:31:52 AM »
Ah, temperature dependency could be a factor. I haven't tried mine outside in the cold, the weather has sucked big time from about the beginning of November. Now that we get -20C in the following days, sun light should be available instead of the continuous overcast (yay November and December in Northern Finland, but we get the compensation in March) for the last two months.

Perhaps there is indeed something related to thermal expansion and the build material. It really does not take a lot of thermal expansion to throw the autofocus off, and makes me wonder whether some amount of complaints of the 50EX or 50L are caused by that too.

Given the Sigma's new Thermally Stable Composite, it is indeed possible that therein lies part of the problem. Could you provide a link to the Facebook group? The most burning question from my part is whether there is hysteresis with respect to the temperature involved. That would mean that taking the lens (calibrated at +20C) from +20C to -20C and using it there, then bringing it back to +20C indoors does not return the lens to the earlier calibrated position.

Third Party Manufacturers / Re: Have you repaired your 50 Art?
« on: December 20, 2014, 04:18:04 PM »
Well, my question was exactly that: when it misses back and forth, how much in metres does it miss (variance)? I suppose it wont be fluctuating between MFD and INF if you are pointing it to an object at the proximity of minimum focus distance, but instead object distance +/- 0.5 metres or something like that.

By supplying this kind of information to Sigma, that could help pinpointing what's not working right if it is a mechanical error. In this case, it should help to estimate the magnitude of element movement error, whatever causes it.

You could also take a look at the focus scale when it's focusing. In my case, there was a weird jerk when the lens approached the right focus spot that seemed to throw it off. It went away after the service if I recall. I haven't used the lens for two months now as the weather has royally sucked here.

Also, try to find the Sigma contact of this guy: Apparently, making it public also helps.

Third Party Manufacturers / Re: Have you repaired your 50 Art?
« on: December 20, 2014, 03:19:26 PM »
The thing I'm thinking is did you follow the earlier thread about 1DX not working properly in AF Servo and 12 fps in darker areas? I thought that there could be a remote possibility that since you are from Norway that within 6 months, the average luminosity of the scenery has changed drastically. This would be specifically compounded by using 50/1.4 which would naturally be taken to more darker areas than the other lenses.

I actually didn't ask for the 24-70 results. It's a F/2.8 case, thus the usage profile is likely different from 50/1.4, while 200/2 could encounter a bit more similar stuff. Nevertheless, since 200/2 doesn't show similar problems in similar illumination, then the problem is most likely the lens.

What I meant by variance is that people are saying that autofocus is not consistent regardless of the focus distance. The meaning of this, however, is not very clear to me. Does it mean you get front and back focus both within certain limits regardless of the distance, or that the amount of the front and back focus is random regardless of the original focusing distance?

For example, focus it to 5 metres, and the realized plane of best focus has a variance of +/-1 metres from it. Do the same to 10 metres, and you get +/- 1 metres or something like that from it too randomly. OR, is it so that you focus it to 5 metres, and the resulting plane of best focus is from MIN to INF, and when you go to 10 metres, the same happens?

But it does start to sound like mechanical wear of some focusing parts, or like a decoder wheel reader skipping some pulses randomly. However, it could also be the firmware, but it's a bit hard to believe since it works in the beginning. Warm and cold cycles could off-set something inside the lens too.

I haven't opened the lens yet so I don't know much about the inner mechanical construction. Perhaps Roger Cicala from Lensrentals would know something about this?

Third Party Manufacturers / Re: Have you repaired your 50 Art?
« on: December 20, 2014, 02:24:58 PM »
Well, there's two other things that come to mind: first, what autofocus mode are you using? Servo or One Shot? Do you take burst shots or single shots? The second thing, have you used 200/2 with a similar profile?

The logic behind the second question is the following:
The 200/2 should show depth of field being inconsistent even more easily than 50A if this is a camera body issue (like the distance to the AF sensor changing for a reason or the other).

The third thing is that does the lens show the same behavior with a camera body other than 1DX?

When the lens misses, what is the variance of the misses?

Third Party Manufacturers / Re: Have you repaired your 50 Art?
« on: December 20, 2014, 09:49:01 AM »
I had some initial difficulties with 50A, but after service and calibration with the USB dock it has worked fine. Granted, the weather has not been photographic for two months here, but still.

The 50A is far more reliable than EF 50/1.4 with the center focus point, and I trust my 5D outer focus points only on bright and sunny days anyways and when my object is not too close with about any objective I have.

What I recall is that the non-central focus points did not work well with 50A, but they don't either with EF50/1.4.

It does make me wonder whether varying lighting conditions can throw the 50A focus calibration off. I do recall seeing that the results were slightly different when adjusted under room lighting and under sun light. The other thing I can think of could be repeated thermal expansion and contraction.

I don't think that is an issue with the lens hardware at all. I think this has more to do with lens+body combination in the auto-focus routines. The good news is, firmware update will likely correct this, but you'll have to make noise towards Sigma. There's a similar story of a firmware update improving Sigma's 120-300 considerably. Because of that, I do believe Sigma is going to do something about it.

And come to think of it, Canon EF 50/1.4 isn't reliable with the edge points either when using F/1.4. Heck, it isn't reliable even with the center point!

Third Party Manufacturers / Re: Sigma 50 1.4 Art NOT bokehlicious?
« on: July 27, 2014, 02:11:07 PM »
Here I'll have to disagree. 50/1.4 A is yet to leave me down on the bokeh department.

Lenses / Re: 3 week trip to Finland & Germany, what lenses to take?
« on: July 27, 2014, 02:04:56 PM »
Additionally, Finnish cities have great support for bicycle travel, and that's actually quite handy and nice transportation method in the summer time - a bunch of people prefer it over cars and public transportation. If you think of doing that, you'll need to consider reducing the bag weight as much as you can.

Which is why I thought it would be better to know what are you planning to do?

Lenses / Re: 3 week trip to Finland & Germany, what lenses to take?
« on: July 27, 2014, 05:58:34 AM »
Hi there! First of all, last three weeks have been pretty warm here in Finland. Temperatures have gone up to +32 C on day time in shadow, making this - at the moment - hotter than Germany. Next week though, major rain is expected in the beginning of the week (28th, 29th) so I can't just yet tell how it will continue. Be advised that this is the major summer vacation month generally in Fennoscandia.

So, what do you expect to do around here? In Germany, I believe that will be more about sights and relatives, so I guess 28-135 or 24-105 would work best. Here it's a bit different. Since I don't know where your relatives spent their summer time (could be a summer cottage or a city dwelling), this may affect your lens choice. Sun sets around 23.20, and will rise around 3.30 in the morning in my latitude. This means you don't practically need large aperture lenses for getting more light in July unless you go to dark places like house interiors. And also that the moment of golden light will last considerably longer. Typically, it tends to be not possible to see stars until September.

Staying in a summer cottage and general waterscape around it may push your choice of focal length towards the extremes. 28 or 24 should do fine for wide-angles, but you'll be lacking there if the longest focal is 105 mm when photographing sunsets as occasionally longer telephotos work better there. However, I think that the 24-105 itself should work pretty nicely for almost anything if you absolutely want to carry all-in-one package.

Personally, if the weather remains as it is now, I'd seriously consider taking a point and shoot. Even carrying a 5D and the small EF 50/1.4 sounds like an annoyance in +30C to me so if I had to take a 5D, I'd go with a 50 mm prime. But that's simply because of the weight and temperature, but that's me. If the temperature drops to +22C, then I'd have no qualms of taking another lens with me. When I was in Canary Islands a couple of years ago (in November), a combo of 28/1.8 and 85/1.8 worked well, though even those two felt heavy after carrying them the whole day in a camera bag dangling from the back of the neck.

Traveller Gear insurance is mainly needed for the possible damage that you'll encounter in the luggage handling. Other than that, there are practically no street pick-pockets and I have never heard of anything being stolen from a hotel room here. Of course, you shouldn't leave the camera unattended to a bar table, or leave anything of value to a traveller's hostel where rooms are shared, but hotels are a different game. In Germany, it's pretty much the same.

Lenses / Re: Sigma 50mm Art 1.4 Focusing problems
« on: July 11, 2014, 12:35:44 PM »
Yep, it's great idea of Sigma's...make an expensive device to get customers to do their work for them.
You pay Sigma to spend you time correcting their sloppy manufacturing errors. Maybe Ford should make cars which only drive properly after you buy their laptop software to interface with it....

Why? It isn't like the Canon objectives themselves wouldn't require work from the owner when it comes to AFMA.

So, I knew I was getting a lens from the first batch. I knew glitches are sort of inevitable with each new product introduction. Then again, it's about my private time valuation. 20 minutes of playing with the dock, and I got a much better lens for 800 €. I never had problems with 35A, or their other lenses. And it's much better than Canon's 50/1.4, and more general purpose than 50/1.0, exactly what I wanted.

Now I wish I could do the same adjustment with Canon's 70-200/4 IS and my 5D. That objective performs well on my 40D, but is not that stellar with 5D...

I might as well start with a general question that goes: "What is Microsoft's role in the future?" Formerly, their cash machine was enterprises and corporate customers, while gathering some from the consumers. However, given their strategy change to Services & Devices type company, it looks like they are going the Apple route to the consumers. The ground work for the taken route is more and more visible with more seamless integration of MS Store and social media integration to the UI.

As a corporate user, though, I don't like this one bit. I don't want Skype, Twitter or FaceBook feeds on my desktop (or OS keeping the services running, taking my precious free CPU cycles). This is why I'm saying Microsoft should tread carefully on what they are about to do.

Now, on what it comes to genius of Microsoft being a competitor in their own ecosystem, the whole thing is not about what is today. It's about what it likely becomes. And there you get the risk of getting undercut by MS if you start to play that game. Given that yesteryear's GoPro could do 4K video in much smaller package than a laptop, I don't see the connection that MS boosted current laptops to be better. It's more reasonable to think that 4K processing power was coming along nevertheless.

The thing here is that MS decided to go to the upper tier stuff where their OEMs never HAD problems to compete with Apple. It's also happens to be their OEMs most profitable segment per manufactured device. You are comparing the consumer level stuff to Apple high-end laptops, but the reality is, Dell, Lenovo and HP all have had high quality laptops offered before Microsoft even tried to enter the area, and they did not have that much difficulties to compete with Apple.

Additional question is, why is the cheap consumer level stuff then staying at "low quality", and the market never gave it a kick to improve? The answer is, there's a market for cheap devices despite their limitations. This doesn't concern the upper tier so much, but when somebody wanted an upper tier laptop [~2000-3000 €], the customer was not typically a consumer, but an enterprise. Enterprises then could get bulk discounts. Well, at least here.

The little chevron your talking about only appears when the screen size or window size is too small to display the entire ribbon. It's an adaptive thing. There is a LOT of functionality in Microsoft products. Microsoft's options are either to drop functionality, which is 100% guaranteed to cause an uproar...or...find some way of making all the necessary tools available even on screens that are too small to display it all at once.

Try using office maximized on a larger screen. That little chevron your bitching about? It'll disappear...and the entire contents of the entire ribbon will show up on the screen.

Sorry, but I find your complaints about the ribbon just an angry dude finding a reason to be angry about something...

Great. Tell optical designer to get a bigger screen! Ever seen how many graphs are useful to keep a look on when doing optical design? They take quite a bit of screen estate... And the only functional way to use Office is to use it full screen, as I did when my attention was paid to those chevrons. The point was, this is nothing but a revamped menu-structure with same amount of hoops as before, but less amount of customization. And the reason I'm angry about this, that's called loss of productivity.

Office STILL hasn't a functional equation editor (Open Office did this years ago), still no useful greek alphabet shortcuts like ALT GR+M for micro, and STILL worse image positioning options than in 2006 version of OpenOffice. For the good sides of Office 2010, it did add better graphics presentation options and streamlined doing graphs. Those were good changes and I liked them a lot - and got frustrated by not being able to use them to maximum extend due to UI.

I'm very glad I don't live in Europe. The EU has demonstrated for decades that it has a fairly anti-business stance, and the penalties they have levied on large corporations are rather extreme at times. It's a punitive system, constantly punishing, punishing, punishing. I'm not really surprised you hold the opinions you do...I guess the actions of the EU make a lot more sense now...

Making a value judgment of somebody's culture is definitely a way to make friends in international business. Sarcasm aside, if you don't know why something is in place, it usually pays to check the circumstances why that is so before doing anything else. Case in point: the privacy requirements do NOT stem from the EU governance, but from the citizens and enterprises themselves. For the question why WE THE PEOPLE in EU are sensitive with respect to that sort of stuff, I think it's better you figure it out yourself.

You HAVE heard of the Amazon Cloud Services, right? Amazon is the world's largest online retailer. They couldn't be that if they hadn't developed the technology to support that kind of infrastucture. It was many years ago that Amazon started offering web services to access some of the technological infrastructure they had built, and today, they are the largest provider of core cloud services (i.e. big data, compute cycles, virtualized hosting, etc.) of anyone. Those services are used by enterprise businesses to host...pretty much anything. Even NetFlix is hosted on Amazon's cloud servers.

Microsoft Azure directly competes with Amazon Cloud Services. Microsoft's Cloud Services (i.e. Office in the Cloud) directly competes with Google's web apps. Overall, Microsoft's cloud initiatives are gaining a lot of ground against their competitors.

Nobody in the corporate world that I know of uses the listed Amazon's or Microsoft's corporate cloud services in EU, or in Japan as far as my experience goes. I believe it works for the US as the companies are subject to the same federal law, forming a general framework around them. Since there is no general groundwork law, you're simply stupid to upload data somewhere that you cannot fully control - again, here. The only reason I had to start using Hangout is because I happen to work also with US companies, and that is the best option for them. Is it my preferred venue of remote conferencing? Not by a long shot.

Valve was pissed that Microsoft wanted to take a small cut of all in-app sales. Again, that isn't a strategy that Microsoft pioneered...Apple already does that. Valve would have the same problem if they tried to create an app in the Apple store.

As for cost, Microsoft takes the same amount as Apple. They always have. As a matter of fact, Microsoft often gives discounts for app developers, as an incentive, to get them onto the platform. Fundamentally, though, app developers on both platforms pay $99/yr to develop apps, and get 70% of the revenue from the sales. Both companies take 30%, which is then used to cover credit card transaction fees, infrastructural support fees, and the companies cut (which is less than 20% for both companies).

Understandably Valve wants to avoid giving cuts from Steam ecosystem. But that's the point: there's other developers that feel the same. Are you seriously trying to downplay the 30 % increase in costs? It's not a small margin and I would expect to get something for the money. Of course, if this is for low cost apps (and I mean the small ones) you may have a point.

However, the future is more disturbing, as it is likely MS is going and try to extend their cut to EVERY SOFTWARE running in their ecosystem, leading to 30 % increase of costs for all softwares - even those that do not benefit from Cloud integration. And unlike with Apple, this surely wasn't part of the deal before, which is why I see developers being rather wary about moves to that direction.

I'm not sure what is "consistent" about UI changes. The only two things that changed between 7 and 8 was the start menu...which became a start screen, and the use of ribbons in the core desktop apps (i.e. Explorer). People on Windows have been using ribbon for years now, so it isn't something new. I haven't heard much about that being a sticking point with potential upgraders, either...the biggest complaints are the start screen. But as you can see from other participants in this thread, the vast majority of the complaints about the start screen are entirely unfounded.

Not to mention, if you really want a start can have it. There are free and cheap utilities to bring it back if that's something you REALLY REALLY want. It isn't enough to avoid upgrading, because everything else about Windows 8 has been improved over Windows 7.

Re-read what I said.
It's only now that 8 is released and Microsoft's strategy is clear, and it seems consistent UI changes are the norm, I'm considering switching to Linux in next computer update. Microsoft actually never made the jump easier.

= Because Microsoft's strategy is going towards Devices and Services, several things can be predicted straight from that. And I don't like what I'm seeing (and that's just me). Coincidentally, because Microsoft keeps on shuffling the UI, requiring me to constantly learn it again, I might make a bigger jump and learn a completely different OS. They never made it easier as UI re-learning is nevertheless ahead. This applies to both home and work.

Lenses / Re: Sigma 50mm Art 1.4 Focusing problems
« on: July 11, 2014, 08:04:49 AM »
A short update:

I got my 50A back from the shop, and lo and behold, the inconsistency was gone. Sigma representative said they adjusted the lens to a standard body, and then returned it. Now the lens was back focusing either when approached from INF or MFD, which is OK from my books as I've tools to correct that. So Sigma dock it is, and 20 mins of adjustments later, I was ready for real life testing.

In the 300 photos I took last evening, I didn't see focus errors, and got a very good keeper ratio. The lens is now working, and actually seems to be sharp enough that I actually need to decrease camera sharpening preset for JPEGs.

EDIT: I'll have to say that this lens rocks! The background blur stopped down is a definite improvement over Canon's 50/1.4!

EOS Bodies / Re: Patent: Canon 55mm f/1.4 & Other Primes
« on: July 11, 2014, 07:53:31 AM »
Interesting, these are actually not Double Gauss type designs, but I'd say they are retrofocus types. Though with 50 mm examples it's harder to see, I may take a look at these when I get back from vacation as I'm still not sure how much negative power does that 2nd lens provide. Groups G3a and G3b have concave sides facing each other, and this is a departure from classical Double Gauss. My gut feeling is that G3a and G3b will be relatively sensitive with respect to element decenters.

Canon has patented retrofocal designs before, but this seems like a more realizable one. I'd say their designers wanted to keep the objective small and light weight, while providing improved image quality and better focusing over the older 50/1.4. Whether these will be released as a product is another thing.

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