Sony Alpha A55/33 ghosting and sigma compatibility problems

[longvale]

Anyone got any more info re this issue with the new A55 before I buy one!?


Newsgroups: rec.photo.digital.slr-systems, rec.photo.digital
From: Bruce <[email protected]>
Date: Fri, 10 Sep 2010 20:29:04 +0100
Local: Sat, Sep 11 2010 5:29 am
Subject: Early problems for the Sony A33 and A55 ...

There are now quite a few reports circulating of 'ghosting' in images
produced by the Sony A33 and A55, with the pellicle mirror being
identified as the cause.

DPReview has now finalised its review of the A55 with specific mention
of the ghosting issue. DPReview attempts to play it down but the
ghosting is a significant issue. Bearing in mind that we are talking
about brand new cameras, with spotlessly clean mirrors, and any
ghosting will only get worse as the ultra-fragile mirror surfaces age
and gather dust and grime.


http://www.dpreview.com/news/1009/10090 ... update.asp


To add to Sony's problems, Sigma has announced that its Minolta- and
Sony Alpha-mount lenses are not compatible with the Sony A33 and A55.
It is clearly as significant problem as it affects **ALL** Sigma
lenses for the Minolta/Sony Alpha mount.


Owners of Sigma lenses can have recent lenses modified free of charge
by Sigma. However, some older lenses will not be able to be modified.


I'm sure Sony would prefer A33 and A55 owners to buy Sony lenses (or
one of the many thousands of unsold Minolta optics that are still on
the shelves). However, anyone with an existing lens collection that
includes Sigma glass may well be deterred from buying an A33 or A55
body.


http://www.sigma-photo.co.jp/english/ne ... 100910.htm

[peterottaway]

This the latest in a number of problems that Sigma have got themselves into from re-chipping to gear stripping. It doesn't bother me as I don't own any Sigma lenses but it is annoying when people get the problem jolly old posterior about and blame Sony not Sigma. Sony like most major companies has done enough silly things without having to take ownership of other peoples poor design decisions - after all Sigma decided to reverse engineer the A - Mount the way they did.

As to whether ghosting is a problem, only time and a few million photos will tell.From the reports I have read it doesn't appear to affect most of the type of photos that I take. Although when I do get my A55 delivered I will be processing normally and not pixel peeping at 200 %.

[bfitzgerald]

So what's the technical reason for this Sigma incompatibility problem? If they worked on previous bodies what's changed since then with these new SLT models?

[Javelin]

the author is talking out of the wrong oriface. He's just trying to magnify what DPR says and spread FUD

Case in point "ultra fragile mirror surface" um there glass ... but I don;t think there weaker than any other glass

And i'd sure liek to see where all these unsold Minolta lenses are!!!

[Contrast]

[quote="Javelin"]Case in point "ultra fragile mirror surface" um there glass ... but I don;t think there weaker than any other glass

[quote]

There is some validity to the original statement, The big disadvantage to DSLR over film is you don't wind on to a new sensor surface with each new shot. Try as I might I can't keep dust off the sensor and it is a "p in a" and risky to clean. With the a33 a55 a pellicle mirror is vital to the image quality too, and it is further forward in the body and slanted too. Time will tell if the mirroring is a problem for durability.

Regarding Sigma lens issues, I don't blame Sigma, They produce some quality lenses that more than give Sony a run for (your) money, at least optically. Competition is what keeps Sony honest.

For me all this type of hassle and uncertainty with Sony reinforces my thinking that Canon is the way to go.

[David Kilpatrick]

Sigma had little choice except to reverse engineer most AF mounts, mainly because they produced lens specifications which the manufacturers did not have and could not make.

There is no point in asking Minolta or Sony for a code reservation for a 12-24mm when Minolta or Sony will never make such a lens - so instead, Sigma used the code identity for the 28-80mm.

Many of the problems with Sigma lenses are due to the limited number of lens identity (two digit) codes originally planned in by Minolta. They only allowed for 100 lenses (00-99) to exist, in all time. Of course they wanted to use these codes themselves. And some of the codes instruct the camera to change behaviour, or produce 'expectations' of certain lens behaviour for focus reset calibration etc.

Sigma has been forced to use codes which most closely matched the behaviour of their lens (number of rotations of focus drive etc). It's not their fault they have created the largest number and widest range of complex, extreme focal length zoom lenses on the market.

David

[Javelin]

Case in point "ultra fragile mirror surface" um there glass ... but I don;t think there weaker than any other glass

There is some validity to the original statement, The big disadvantage to DSLR over film is you don't wind on to a new sensor surface with each new shot. Try as I might I can't keep dust off the sensor and it is a "p in a" and risky to clean.

I don't have any issues cleaning or even keeping the sensor clean. I don;t get why you would think it's such a huge problem to clean the sensor vs cleaning a rear element ? this has been a no issue for a long time with any DSLR



With the a33 a55 a pellicle mirror is vital to the image quality too, and it is further forward in the body and slanted too. Time will tell if the mirroring is a problem for durability.


Doesn't that make it all easier to clean? also Isn;t it harder for anything onthe mirror to be in focus ?


Regarding Sigma lens issues, I don't blame Sigma, They produce some quality lenses that more than give Sony a run for (your) money, at least optically. Competition is what keeps Sony honest.


Well regardless Sigma has made a lot of junk along with their better stuff. The only thing you get with Sond is ensured compatability.

For me all this type of hassle and uncertainty with Sony reinforces my thinking that Canon is the way to go.


then +FUD is working. Canon I would argure is in far worse shape that Nikon or Sony quality wise and I doubt their commitment to the DSLR business (hahaha)

[Contrast]

[quote="Javelin]
I don't have any issues cleaning or even keeping the sensor clean. I don;t get why you would think it's such a huge problem to clean the sensor vs cleaning a rear element ? this has been a no issue for a long time with any DSLR

If it was a "no issue" it wouldn't be a regular thing surely? Simple fact is shaking dust off doesn't always work, and if it does it drops it into the body to go on again later. Regarding manual cleaning, it isn't without hazard, and generally you don't do it unless you have dirt that auto cleaning won't shift, i.e there is a problem, and it isn't just a Sony thing, it is all DSLR...

With the a33 a55 a pellicle mirror is vital to the image quality too, and it is further forward in the body and slanted too. Time will tell if the mirroring is a problem for durability.

Doesn't that make it all easier to clean? also Isn;t it harder for anything onthe mirror to be in focus ?
It makes it easier to contaminate/damage, and obviously the ghosting issue makes it quite apparent that the mirror state can noticably effect an image, in focus or not.

Regarding Sigma lens issues, I don't blame Sigma, They produce some quality lenses that more than give Sony a run for (your) money, at least optically. Competition is what keeps Sony honest.

Well regardless Sigma has made a lot of junk along with their better stuff. The only thing you get with Sony is ensured compatability.
If you want junk take a look at Sony kit lenses.

For me all this type of hassle and uncertainty with Sony reinforces my thinking that Canon is the way to go.


then +FUD is working. Canon I would argure is in far worse shape that Nikon or Sony quality wise and I doubt their commitment to the DSLR business (hahaha) [/quote]
No way I believe Sony is commited to DSLR, I'd easier believe it of a market leader.

[Javelin]

Um no. Sony's 18-55 is the best kitlens of all of the ones recently put on entry cams from any maker. DPR and Kurtmumger and others pretty much agree. in fact the worst one i've ever seen was the non stabilized Canon 18-55 which was even worse than Sony's 18-70... which actually wasn't all that bad if you found a good copy.


Thats the pont Canon keeps selling cameras with software bugs and porr quality components like the kit lenses and they get a pass. Sony hasn't got anything to worry obout from them. at least not for much longer expecially if canon keeps selling top emd DSLRs the pros would rather not use AF on and thiose electric greens are starting to get noticed too I see. Frankly you should switch to Nikon a company with a future!! heh..

[Contrast]

Um no. Sony's 18-55 is the best kitlens of all of the ones recently put on entry cams from any maker. DPR and Kurtmumger and others pretty much agree. in fact the worst one i've ever seen was the non stabilized Canon 18-55 which was even worse than Sony's 18-70... which actually wasn't all that bad if you found a good copy.
I have 2 of the Sony SAL18-70 both from new and they are equally dreadful. I read the DPR review on the 18-55 SAM version and I have a real hard time agreeing with it, I've tried it in a few retailers and the distortion is annoyingly obvious. I wouldn't buy one.

Thats the pont Canon keeps selling cameras with software bugs and porr quality components like the kit lenses and they get a pass. Sony hasn't got anything to worry obout from them. at least not for much longer expecially if canon keeps selling top emd DSLRs the pros would rather not use AF on and thiose electric greens are starting to get noticed too I see. Frankly you should switch to Nikon a company with a future!! heh..

And how many "features" are missing on the entry level Sony or are just not programmed in to begin with? Simple fact is I know many Canon/Nikon users and there is NOTHING I can offer in defence of my Sony. If Sony weren't bugged/bad firmware how come Nikon can get a better image out of a Sony sensor? We probably need to agree to disagree.

[peterottaway]

If Contrast wishes to debate in am informed manner then do so, if you get your kicks out of trolling then I suggest you go elsewhere.

That Sony is neither Canon nor Nikon is a given and can be left at that. Neither was Minolta before it. And everyone has their own preferences and order of priorities when buying their cameras, I will not buy a Sony 2xx/3xx/5xx cameras ( amongst others) as I dislike the penta mirror. I also own both Sony and Nikon FF cameras and have easy access to several Canon DSLRs and am well aware of the pluses and minuses of the major brands.

[Javelin]

There is a big difference between one camera being able to out preform another and shipping expensive products like these with features that fail to function at all. the requiring the customer to add a firmware update to get it working months later. Far more cameras get bricked by firmware updates than get damaged cleaning. your a canon guy you going to say you've never heard of error 70 ? hahah now try and find damages sensors from cleaning.

The 18-55 is a great lens (actually all the new version SAM lenses are top knotch in their markets) whether you believe it or not

I'm sure theres still 7d and 5Dmk2's waiting for you .. And they probably need firmware updates hah!! I don't care about "features" that didn't come with the camera I'd much prefer to have the stuff I paid money for to work the way it's supposed to. I think your just ignoring Canikons problems and amplifying Sony's way out of proportion.

[Contrast]

If Contrast wishes to debate in am informed manner then do so, if you get your kicks out of trolling then I suggest you go elsewhere.

No problems with informed debate
No problems with critical debate
No problems with being prepared to see pros and cons
Big problems with one sided debates, are we only allowed to post glowing comments?
Big problems with starting personal mud slinging

End of...

[Greg Beetham]

There's nothing to say you can't use MF with any Sigma lens, just turn AF off, save some battery power and focus manually, with a little practise you'll find it's easy to do, and you won't ever have to worry about breaking anything, it's a small price to pay for in some cases very fine optics, you might have to set the shutter button option accordingly, from focus priority to shutter priority.
Greg

ps. I'm assuming of course that the incompatibity issue is related to AF, I haven't heard of any other particular Sigma problem regarding compatibility with Sony cameras, except maybe A-mount lenses not focussing on the NEX, but all A-mount lenses are in the same boat there regardless of brand...no great biggie really, again just use MF.

[agorabasta]

The problem with Sigma on SLTs is related to the aperture mechanism and not to the focusing. And the problem seems to be at least partially mechanical in nature - no firmware change can help here. (There's some writeup on the matter at the IR.)

Actually, I have a suspicion that the Sigma lenses often have their aperture lever end placed too deep - as simple as that.