JensR

Lives in United Kingdom Bath, United Kingdom
Works as a Mechanical Engineer
Joined on Nov 23, 2003
About me:

Hi,

thanks for stopping by!
If you want to see what I'm up to, send me a message :)

My 'plan':
Talk Pentax into a digital Electro-Spotmatic! (This needs some work...)

-------------

Older Signatures:

'LBA knows no bounds, and seeks no justification...' (Jim King, 2005)
http://www.jr-worldwi.de/photo/index.html - Photography, Tech and Geek stuff :}

'Why is everyone answering rhetorical questions?' (Me, 2005)

'Well, 'Zooming with your feet' is usually a stupid thing as zoom rings are designed for hands.' (Me, 2006)

'I only trust those photos I have faked myself.' (Me, 2007)
http://www.jensroesner.de/

--=! Condemning proprietary batteries since 1976 !=--

'I don't want them to believe me, I just want them to think.'
Marshall McLuhan

Comments

Total: 453, showing: 41 – 60
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In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

Well, then thank you for the support @guyfawkes

FWIW; If you start a message with

"
@JensR.

You're beating yourself around the head, and you won't get anywhere.
"

It is difficult to not think you are addressing me with this ;)

Link | Posted on Jun 5, 2018 at 14:12 UTC

goes a bit beyond my snorkeling and taking mental images. Super!

Link | Posted on Jun 4, 2018 at 20:31 UTC as 9th comment
In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

@guyfawkes

Have you actually read what I wrote?
I said: "There is no perspective distortion, there is only perspective." Not once are you referring to "distortion". Are you confusing me with someone else, maybe? Your criticism has little relevance to what I am saying.

All you do is spend three comments in telling me that perspective changes when location changes. Do you really think I don't know that? I said it here.

But then you say:

"All that is happening is that by changing focal lengths and shooting distances he is effectively controlling and making use of perspective."

I think you need to be more precise with language. What you said was at least misleading. Here is the corrected version:

"What is happening is that by changing shooting distance he controls and makes use of perspective. Then he selects the appropriate focal length to give the subject magnification he wants."

This is clear in what affects what and removes the vague "effectively" for clarity.

Link | Posted on Jun 4, 2018 at 20:17 UTC
In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

> The big nose guy is taken with a big FOV, and therefore MUST be taken by a wide angle lens.

No. As the video explains, you can create a matrix panorama with a narrow angle lens.

In any case, that has nothing to do with there not being perspective distortion, there is just perspective.

> But, assuming it is not cropped, then it must be a tele lens.

What is this supposed to prove :D "It is either a crop or it must be a tele." Well yes. That's how perspective works.

> So - the first picture illustrate "wide angle perspective".
> So - the second image illustrate "tele perspective".

First one shows close-up perspective, second shows far-away perspective.

You seem to think "distorted" is a synonym for "unusual" and you won't see me agreeing with this. So can we end this now?

Link | Posted on Jun 1, 2018 at 20:14 UTC
In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

Wow. Let me repeat this and highlight a key word:

"There is no *special* perspective in tele photos."

Link | Posted on Jun 1, 2018 at 19:38 UTC
In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

Evidently we don't.

> Therefore the compressed perspective you see in tele photos

There is no special perspective in tele photos. If you take the photo with a wider lens from the same spot, you get the same perspective. If it is the same perspective, it cannot be distorted.

Link | Posted on Jun 1, 2018 at 19:29 UTC
In reply to:

winkalman: Thanks for the re-shoot DPR. As with all cameras, the K1 (either version) is a compromise but they're still arguably the best landscape cameras available for under $2k. Pentax is only a niche player but it's nice to see that they can still deliver great value within their product range.

Point being is that the K1 is a rugged camera.

> architectural (T/S lenses available), fashion, food, night, astro, conceptual, fine art, portrait, and still life.

I am not sure I would recommend to use the K1 on a fashion runway show with AF in variable light. The other topics are either related to landscape (in my definition anyway) or can be done just as well but more cheaply with a camera that is not as rugged as the K1, which is what I think winkalman was thinking of.

Link | Posted on Jun 1, 2018 at 19:26 UTC
In reply to:

Rico: Carey I don't know how DPR can still be claiming the Accelerator Unit is reducing detail and lowering contrast as ISO increases let alone claim the K1MKII images are inferior. The K-1MKII is clearly doing a better job at maintaining better value both for color and blacks whites and greys. This is entirely due to the Accelerator Unit.

The Accelerator Unit is third generation in K1MKII. When Ricoh/Pentax introduced the Accelerator Unit in the K-70 and KP DPR praised the high ISO performance for these cameras without ever mentioning the Accelerator Unit by name.

Who made DPR the gate keeper on when "Noise Reduction" should and should not be used? Seriously whether you like it or not every brand is applying "Noise Reduction". That is the whole nature of the algorithms.

Using the FA77 and the 85mm for the Nikon introduces purple fringing. It can be clearly scene along white edges like the white triangles. Plus the Studio Scene isn't linking the ISO as you increase it for each camera.

Mira, dpreview have discussed unraw-RAW in the past and did detailed studies on compressed RAW as well as noise suppression in RAW.

Also just because some RAW processing is generally (but not always) accepted (pixel mapping, darkframe subtraction) doesn't mean that all RAW processing is beneficial.

DPreview in their capacity of well-informed reviewers have identified an issue, informed the public about it and allocated a score to this. They do this for each camera where there are such issues.

I say that has a Pentax user with an interest in Sony's A7 family - both cameras have been scrutinised by dpreview and I'm thankful for that.

Link | Posted on Jun 1, 2018 at 19:21 UTC

Thank you for fixing this so thouroughly!

What I take away is that my K1 is actually sharper than originally measured. ;)

Seriously, the K1 is a great camera. If you need a sturdy high-res affordable outdoorsy camera for landscape photography, it is worth a consideration even in 2018.

Link | Posted on Jun 1, 2018 at 19:12 UTC as 64th comment | 1 reply
In reply to:

faberryman: The fact that they had to hand pick a 77mm lens says something about their QC as well.

Given the issues that were found with the reviews, it makes 100% sense that both dpreview and Pentax did not want to do another iteration. If you go to photozone.de you will find lots of lenses from all walks of life that have had issues.

Link | Posted on Jun 1, 2018 at 19:12 UTC
In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

> Please read all I have written

I have Roland, I have.

> The reason why a tele lens has a compressed perspective is that you move further away from the subject,

A lens does NOT have a perspective. That is the whole thing.

> The perspective looks distorted compared to a standard lens.

No, it does not. Take a standard or wide lens, crop it to the FOV of the long lens, same visual (but bad resolution).

Also "looks distorted" is different from "is distorted", but let's not nitpick.

> And please, do not misinterpret what that means again

I have not misinterpreted a single thing you said. We have a disagreement about terminology, not a misinterpretation.

> There is no problems with the term.

There is and I have explained it to you. Distortion means that something is not as it should be. There is no perspective distortion. There is only perspective.

Link | Posted on Jun 1, 2018 at 19:02 UTC
In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

No worries, I did not take it personally.

And again, the perspective is not distorted - perspective does not change by changing the lens. Perspective changes by moving the camera. The video shows that and anybody with a crop tool can verify that.

What you mean could be described as "unusual subject distances" - a tele lens allows you to take a photo of a tree from a mile away, a wide angle lens allows you take the photo from 5m away. Would you say "distorted subject distances"? I wouldn't. I don't think anything is distorted here.

Link | Posted on May 31, 2018 at 23:14 UTC
In reply to:

jhinkey: No, it would not be nice as it will be the death of Nikon if they only make a niche FX mirrorless camera.

And Richard, really?:
"For me, telephoto lenses ruin mirrorless cameras. There, I've said it.

Telephoto lenses for mirrorless are just as long as their DSLR counterparts, so there's no size benefit to throwing away your mirror. Worse still, these long, heavy lenses demand that mirrorless cameras develop the bulky, bulbous grips that SLRs have evolved since the 1990s."

Have you not evolved past the tiresome "mirrorless is only about smaller camera & lens sizes" argument?

Next time I see you in Glazers we're going to have to have a little talk . . .

> The Pana Nocticron & Oly f1.2 primes are a smidge smaller (or no larger at worst) than the very nice (and much cheaper) Sony FE 85/1.8,

Proving my point again. equivalent f/2.4 same size as native FF f/1.8.

> My original point is that we *could* have more smaller FF glass like the 35/2.8, the powers that be have just decided that's not what sells, maybe it isn't..

I think we are actually agreeing and somehow crossed wires. :D

Of course "dark" FF lenses are physically possible and they would be tiny, but there is no market to it. because we can just use a "medium" lens on an APS-C system and still have overall a smaller/cheaper system.

This whole discussion started by me agreeing that a modern APS-C sensor has resolution and dynamic range on par with an older FF sensor (such as in the A7ii) . In such a case, there is basically no reason to go with FF unless you want the better DOF control.

Nothing you have said contradicts this, so I think we actually agree?

Link | Posted on May 25, 2018 at 14:10 UTC
In reply to:

JensR: Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

I am not confusing anything Roland, please read it again. You frequently do this, you read something someone writes and you misinterpret that based on your pre-conceived ideas of what people might mean. It is getting rather annoying, frankly, Roland.
I discussed the meaning of distortion and gave an example of distortion that photographers know. I could also have talked about audio distortion. At no point am I confusing perspective with lens distortion.

And it does not lose any information - it removes a misleading term.
There is no perspective distortion. You are just proving why it is important to remove "distortion" from this term, because *you* are confusing things.

Link | Posted on May 25, 2018 at 13:47 UTC
In reply to:

jhinkey: No, it would not be nice as it will be the death of Nikon if they only make a niche FX mirrorless camera.

And Richard, really?:
"For me, telephoto lenses ruin mirrorless cameras. There, I've said it.

Telephoto lenses for mirrorless are just as long as their DSLR counterparts, so there's no size benefit to throwing away your mirror. Worse still, these long, heavy lenses demand that mirrorless cameras develop the bulky, bulbous grips that SLRs have evolved since the 1990s."

Have you not evolved past the tiresome "mirrorless is only about smaller camera & lens sizes" argument?

Next time I see you in Glazers we're going to have to have a little talk . . .

An APS-C lens that is f/1.2 will very likely not be smaller and certainly not smaller and cheaper than an FF f/1.8 lens of the same angle of view. Happy to be convinced otherwise, but I'm not going to trawl through hundreds of lenses to compare, but you only need one or two to prove me wrong.

Edit: have to correct myself there. I guess there might be some manual focus 50 or 55 f/1.2 lenses that when used on APS-C give the DOF control of roughly a manual focus 85/1.8 on FF but are slightly smaller. So a draw, basically. Outside of this region, though?

> it doesn't mean you're giving up all notion of DoF control,

Well, of course not - If you only want to control DOF as well as APS-C allows, then get APS-C. If you want more, get FF. That's what I said, albeit abbreviated. It should be pretty clear that I was not implying that APS-C users only work fully stopped down ;)

If you want an f/2.8 FF prime, get an f/1.8 prime and mount it on APS-C ;)

Link | Posted on May 24, 2018 at 23:22 UTC
In reply to:

jhinkey: No, it would not be nice as it will be the death of Nikon if they only make a niche FX mirrorless camera.

And Richard, really?:
"For me, telephoto lenses ruin mirrorless cameras. There, I've said it.

Telephoto lenses for mirrorless are just as long as their DSLR counterparts, so there's no size benefit to throwing away your mirror. Worse still, these long, heavy lenses demand that mirrorless cameras develop the bulky, bulbous grips that SLRs have evolved since the 1990s."

Have you not evolved past the tiresome "mirrorless is only about smaller camera & lens sizes" argument?

Next time I see you in Glazers we're going to have to have a little talk . . .

If you are not interested in DOF control, then yes, get a modern APS-C over an old FF camera.

Link | Posted on May 24, 2018 at 17:43 UTC

Been saying that for years and I go a step further: It's not "perspective distortion" - it is just "perspective". Distortion means something is not as it should be, whacked out of shape, like a lens reproducing straight lines as bent lines.

Link | Posted on May 24, 2018 at 17:41 UTC as 34th comment | 21 replies
In reply to:

jhinkey: No, it would not be nice as it will be the death of Nikon if they only make a niche FX mirrorless camera.

And Richard, really?:
"For me, telephoto lenses ruin mirrorless cameras. There, I've said it.

Telephoto lenses for mirrorless are just as long as their DSLR counterparts, so there's no size benefit to throwing away your mirror. Worse still, these long, heavy lenses demand that mirrorless cameras develop the bulky, bulbous grips that SLRs have evolved since the 1990s."

Have you not evolved past the tiresome "mirrorless is only about smaller camera & lens sizes" argument?

Next time I see you in Glazers we're going to have to have a little talk . . .

Depends on what you are looking at. Resolution and dynamic range, okay, but The A7ii is pretty much at APS-C price now and it still offers DOF control beyond any APS-C system.

Link | Posted on May 23, 2018 at 18:33 UTC
In reply to:

jhinkey: No, it would not be nice as it will be the death of Nikon if they only make a niche FX mirrorless camera.

And Richard, really?:
"For me, telephoto lenses ruin mirrorless cameras. There, I've said it.

Telephoto lenses for mirrorless are just as long as their DSLR counterparts, so there's no size benefit to throwing away your mirror. Worse still, these long, heavy lenses demand that mirrorless cameras develop the bulky, bulbous grips that SLRs have evolved since the 1990s."

Have you not evolved past the tiresome "mirrorless is only about smaller camera & lens sizes" argument?

Next time I see you in Glazers we're going to have to have a little talk . . .

I am sure Sony will in time introduce an A5 which will be roughly the size of the first A7, but with Ibis. Until then, the A7ii which can still be bought new, is a "small full frame mirrorless" for me.

Link | Posted on May 23, 2018 at 13:38 UTC
In reply to:

panther fan: The Canon FD mount is the perfect example, showing that making a clean cut may cause some short term anger, but the benefits in the long run are worth it. Just cut it, give some basic compatibility via adapter, like Sony with the LA-EA3 and then move on.

yeaaaaah, buuuuut ... it would have been possible to keep the EF advantages and provide basic adaptability for FD lenses. While I think the EF mount was absolutely genius and am very aware of the drawbacks that Nikon and Pentax suffered from by (initially) going for full compatibility, it would be wrong to say that the cut has to be 100% to be "clean" (at least from an engineering perspective).
Incidentally, your argument about the various Sony -Amount adapters points to the same.

Link | Posted on May 23, 2018 at 13:36 UTC
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