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10-21-2016, 09:49 AM   #166
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QuoteOriginally posted by photoptimist Quote
I've never seen so much blatantly incorrect nonsense about optics in my life. For example, yes, glass does "slow down light" but the light speeds back up the instant it reaches air between the lenses or as it travels to the sensor. Glass is not a capacitor. Most of the light loss is not in the glass but in the surfaces between air and glass. In that regard, a modern lens with better coatings may have less light loss than an older lens with worse coatings even if the newer lens has many more elements. The bigger front elements of modern lenses have nothing to do with light loss... I could go on but suffice to say there's probably almost no correct explanations in the entire blog.
That blog has been discussed before on the forums. Most people agreed that in some sense there might be something to what he is saying, but that there are more complex mechanics at work. Just in case you are interested.
Still, there is some correlation with older lenses a certain type of rendering, and newer lenses with another type of rendering. And it happens that older lenses tend to have different lens coatings and fewer, perhaps less-complex elements (for obvious reasons, technology simply wasnt as advanced then)

10-21-2016, 05:03 PM - 1 Like   #167
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QuoteOriginally posted by photoptimist Quote
Glass is not a capacitor.
I actually cackled out loud with that one - I cant wait for the day where I uncap a lens, give it a tap, and get blasted with photons that have been stored for a week... haha
10-21-2016, 05:10 PM - 1 Like   #168
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QuoteOriginally posted by mattt Quote
I actually cackled out loud with that one - I cant wait for the day where I uncap a lens, give it a tap, and get blasted with photons that have been stored for a week... haha
"I needed to take some photos, but my camera was at home. Luckily my 50mm was on me, so I just kicked over to standby mode, I'll offload the images to the sensor when I get back."
10-22-2016, 02:03 AM   #169
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Wow. For a moment I thought it's "The Onion" of optics/photography... but I'm afraid he's serious. Glass is a capacitor? Each colors move at a different speed towards the sensor? He should learn the basics, before teaching others.

I remember some clown ranting on the same subject, with a practical example - the nice looking, but flat figured Asian woman was shown as an example of the flat rendering of modern lenses, while the longer-nosed Caucasian, as how things are rendered with an older lens.
Was he the same idiot?

10-22-2016, 08:28 PM   #170
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QuoteOriginally posted by photoptimist Quote
My goodness!

I've never seen so much blatantly incorrect nonsense about optics in my life. For example, yes, glass does "slow down light" but the light speeds back up the instant it reaches air between the lenses or as it travels to the sensor. Glass is not a capacitor. Most of the light loss is not in the glass but in the surfaces between air and glass. In that regard, a modern lens with better coatings may have less light loss than an older lens with worse coatings even if the newer lens has many more elements. The bigger front elements of modern lenses have nothing to do with light loss... I could go on but suffice to say there's probably almost no correct explanations in the entire blog.

There may well be good physical reasons for the differences in how older versus newer lenses render images, but Khong's reasons are not it.
Where we see major differences in the visual properties in how the final image is going to be rendered has more to do with what that lens was designed for.

Often times the lenses that are being compared New vs old are lenses are designed around general use being compared to older specialized lenses designed for their portraiture work, there is a reason why such lenses when designed fetch a premium and they still do take a look at some of the new specialised lenses
10-23-2016, 05:54 AM   #171
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QuoteOriginally posted by Na Horuk Quote
One thing you can do is go here: Pentax Camera & Lens Sample Photo Search Engine - PentaxForums.com
Now look at photos taken with classic portrait lenses like FA 77mm ltd, or DA* 55mm f1.4. Compare those to Pentax 100mm macro, Tamron 90mm macro. The difference will become apparent quite soon (even though you can compensate for this with good technique, lighting), but it depends on you whether you want to spend so much money on that difference. I didn't! I have a DFA 100mm, but the most "portrait" lens that I have is probably the very affordable Helios 44-2. I don't really take portraits, not a priority of mine right now
Thats most of what im getting at. My 90mm macro not being a portrait lens doesnt stop it from making nice portraits, and a much much more expensive lens, that only does one thing, may only do a little better.

Last edited by unixrevolution; 10-30-2016 at 02:35 PM. Reason: spelling error
10-30-2016, 08:01 AM   #172
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QuoteOriginally posted by unixrevolution Quote
Thats most of what im getting at. My 90mm macro not being a portrait lens doesnt stop it from making nice portraits, and a much much more expensive lens, that only foes one thing, may only do a little better.
In fact maybe even saying "portrait" vs "macro" is a bit too much. Let's say that many lenses do have a kind of rendering that is gentle, with great in focus/out of focus transition that give a 3D look/pop without being agressive on the subject. This comes from portrait lenses, but this also come with the lens era too. FA lenses are much more like that to me than DA lenses. I don't know the FA macro lenses. But I wouldn't be surprise to see they have different rendering than current macro lenses.

Then there some lenses that do have a very contrastry look, many even have outstanding flare resistance, quite visible microcontrast and a different more aggressive rendering. Some of theses are specialized for short focussing distance and provide 3D/pop at theses focussing distance with nice bokeh even if sometime their bokeh is not as pleasing for longer focus distance. The DA lenses (except for the focus distances), in particular the DA ltds are like that. A bit less for the DA70, maybe for a reason, I don't own it so I wont insist but for the DA lenses I tried (DA15, 21, 35ltd, DA40) there clearly that even if DA21 rendering is quite less aggressive than the others.

So either you are rich and then you get it all, use each when it is best, or maybe you get what you like most, regardless of price. Or maybe you want to optimize the spendings and may take a cheap lens that does reasonnably well in many circonstance and get done with it. At worst, post processing can correct things a bit too.

In the end, I am a F/FA rendering fan. For now "only" FA31, FA77 but also F135. I have also some DA: DA15, DA21 and sold DA35 ltd. I perfectly see the difference, where even they perform significantly better than their FA counterpart but I prefer the FAs.

I am sure you can make a macro lens shine for portraiture, as anyway, photographers skill, subject and lighting are more important than gear. It will make things a bit harder and another photographer, as skilled might leverage dedicated portrait lens to give the classic expected look of a portrait better. And maybe overall a majority of people may prefer that.

I did say "classic look", because honestly we speak of art and color rendering. this is subjective and there no absolute. I am convinced that for some portraits, you can get better results with a macro lens than with a classical portrait lens depending what you are after. But this would be a bit a master at work really using the tool to get exactly what he intended.

Last edited by Nicolas06; 10-30-2016 at 08:06 AM.
11-14-2016, 06:26 AM   #173
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They have brought up the new 85mm f1.4 in the art series but not yet in pentax mount.

11-14-2016, 08:16 AM   #174
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DPR has samples from the new 85mm posted today.
11-14-2016, 10:53 AM   #175
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Look fine but the old one was fine already
11-18-2016, 07:25 PM   #176
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QuoteOriginally posted by D1N0 Quote
Look fine but the old one was fine already
Indeed the old one is a lovely lens.. my favorite so far.. i was reading a review today about the art and looks a that is more accurate and perform faster.. price ofcourse is higher.. let see if it comes to the K mount, same as the other Art lenses.
11-27-2016, 05:12 AM   #177
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Lenstip reviewed the new one: Sigma A 85 mm f/1.4 DG HSM review - Summary - LensTip.com
11-27-2016, 09:58 AM   #178
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QuoteOriginally posted by D1N0 Quote
Ouch. Seems pretty clear conclusion to me. Kudos to Sigma.
11-27-2016, 10:23 AM - 2 Likes   #179
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spec sheet geeks unite - your god of clunkiness has arrived

QuoteOriginally posted by D1N0 Quote
I find it funny that lens "testers" don't even find the skill to include the quality of size/weight of a lens in the rating. They kind of Rishi'd the whole thing.

1130 g for a prime.

The DA* 50-135mm is 685 g.
FA 77mm F1.8 is 381 g.
The DA* 60-250/4 is 1.040 g

Whatever lenstip put up in the list of their "pro" opinions is IMHO completely outweighed (sic) by the monstrous clunkiness of the lens.

The old Sigma 85 quality of size and weight was a little less than a pound (!) better than the current version (really bad downgrade here) and still I have yet to hear anyone who is not dependend on commercializing photography but does it for the fun of it (the 99%) who ever said he liked to carry the old 85mm one with him.

If a prime is not significantly smaller and lighter than a zoom lens, it is a crappy lens design.

Good for the spec / MTF sheet geeks, not really attractive for consideration for anyone else even when the price drops to a third of the current.

Just my 2 cents.
11-27-2016, 01:53 PM   #180
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I'm keeping my DA 70mm Limited until I get confirmation that the new Pentax D FA "Large Aperture Medium Telephoto Single Focus Lens" weighs well under 1kg.
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