Anti aliasing simulator filter


python118

Link Posted 13/01/2016 - 13:02
Hi, am fairly new to the k3, at the moment i have the aa filter switched off what difference is it going to make for me if i use it

Regards Dave

johnriley

Link Posted 13/01/2016 - 13:08
The AA filter is used in digital cameras to slightly blur the image. This means that the chance of intereference patterns (moire) being seen in fine detail is reduced. A simple example of moire is the shimmering of a herringbone jacket on a TV screen.

However, many cameras are much higher resolution than they used to be and therefore the AA filter is being ditched in favour of sharper images. If you have a suspect subject then it can be switched on to reduce the moire patterns.

Moire is quite difficult to induce though, so I'd keep it switched off in almost all situations.
Best regards, John

McGregNi

Link Posted 13/01/2016 - 14:06
It's interesting, isn't it, that the 'AA Filter Simulator' (a function using the sensor shake technology) was introduced with the K3, the model immediately after the two K5II / K5IIs models. These offered a clear choice ... But you either had a (real) AA filter or you didn't....too late once you'd made your choice.

So it is easy to see the new K3 option as providing a catch-all solution.... No need to choose, you can have both in the same camera.

Most people say just leave it off, like John above. The simulator may provide some reassurance and feel good factor, but its the practical application that is more tricky .... The problem is that moire cannot always be exactly predicted, or may not be detected on the LCD screen when shooting. We have the technology but we don't have a reliable workflow method to guarantee that we will use it effectively when needed.

As such the risk is there that the benefits may well be wasted in practice.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Last Edited by McGregNi on 13/01/2016 - 14:07

johnriley

Link Posted 13/01/2016 - 14:21
The question is, how often do we get moire? When I reviewed the K-3 models I found it quite difficult to find a subject that would induce moire.
Best regards, John

McGregNi

Link Posted 13/01/2016 - 14:34
So its not a feature you would recommend specifically paying for then ? Although, interestingly, we did have to, because the K5IIs was MORE expensive ! Now perhaps the cost is very little .... ?

Out of interest, we seem to have left the era of aa filters on our digital sensors (I believe both the K-S1 and K-S2 are without.) But do those 'entry to mid' range models include the simulator, or is that a high end feature to be paid for on the top of range models?
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Last Edited by McGregNi on 13/01/2016 - 14:43

johnriley

Link Posted 13/01/2016 - 15:05
We paid more for the K-5 IIs presumably because it was a variant that was expected to have a smaller production run. No doubt it was an experiment to see how it was taken up.

IIRC all the subsequent cameras where there is just the one model have the AA simulator, so the choice is built in and we pay nothing extra for either option.
Best regards, John

McGregNi

Link Posted 13/01/2016 - 18:49
Certainly then its a good example of a high end feature coming into the next models down extremely quickly. As such they offer amazing value really. It's just a question of whether users would find a practical and reliable method of assessing the actual need when in the field.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver

richandfleur

Link Posted 13/01/2016 - 19:48
Personally I see it as a gimmick, intended to offer a point of difference. I expect it to almost never be used on most cameras with the function.

As John mentions the cameras are now pretty darn good, so moiré doesn't appear to be a common problem as much any more. And as Nigel points out, it's often extremely difficult to predict the occurrence, so most often it will be spotted to late to retake the shot.

Personally I find there are tools to deal with it (to some degree) in post, available via the likes of Lightroom or more manually via photoshop, so I'd take my chances with it off. The exception being that one time you get a job to photograph lace curtains or pin stripe shirts etc,

python118

Link Posted 13/01/2016 - 20:21
Thanks for the replies, so if I am taking images of deck chairs its going to be in my best interest to use it

Dave

johnriley

Link Posted 13/01/2016 - 23:30
I don't think deck chairs will be a problem Dave. I presume you're thinking of the pattern in the cloth, but I suspect it will take more than that to show any moire effects.
Best regards, John

pentaxian450

Link Posted 14/01/2016 - 00:54
Sometimes, I wish I could install a real AA filter on the K3.

The simulator doesn't work with shutter speed above 1/1000 sec.

P.S. Sometime, when reviewing image on the rear screen, some moire will show up because the screen resolution isn't high enough. It doesn't mean moire will show up on the picture.
Yves (another one of those crazy Canucks)
Last Edited by pentaxian450 on 14/01/2016 - 00:56

richandfleur

Link Posted 14/01/2016 - 01:04
pentaxian450 wrote:


P.S. Sometime, when reviewing image on the rear screen, some moire will show up because the screen resolution isn't high enough. It doesn't mean moire will show up on the picture.

Exactly. And vice versa I presume. I expect you'd need to zoom to 100%, if that is an option on the rear screen? (- from memory it goes to a max of 16x zoom, but I don't know if that equates to 1:1?), and then pan around the image looking for moiré ...

You're quite limited really, and presumably need to go on gut instinct and assessment of the subject matter. I like that it's an option, but I do think it's over hyped to promote a point of difference at release time. Personally I'd rather them take that sensor shift tech and use it to stabilise during video mode...

McGregNi

Link Posted 14/01/2016 - 05:34
We need a good 'tutorial' on it then ....'A Method of Applying Gut Instinct' .....
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver

richandfleur

Link Posted 14/01/2016 - 05:55
McGregNi wrote:
We need a good 'tutorial' on it then ....'A Method of Applying Gut Instinct' .....

Lol, same way most people get it I expect. Go out shoot lots, stuff up shots, work out why, repeat until getting better

http://youtu.be/ZFteoCptzvM

SteveLedger

Link Posted 14/01/2016 - 06:37
richandfleur wrote:

http://youtu.be/ZFteoCptzvM

YouTube comment: When the moon hits your eye like a big pizza pie, that's Moiré
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