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: 71, showing: 1 – 20
« First‹ Previous1234Next ›Last »
In reply to:

Janoch: Seriously good looking... could be the wide, I need.

Look forward to reviews!

Price sounds totally wrong though?

Has the price been removed from the page or am I just too blind to see it?

Link | Posted on May 17, 2016 at 11:35 UTC
In reply to:

mrgooch2008: The problem it has is you can't adjust the level on it.

you can adjust the legs.

Link | Posted on Apr 27, 2016 at 16:32 UTC
In reply to:

Earth Art: So this filter only has a scale that goes from max to min? It would be more handy if it had some marking for different stops. Seems like using anything other than min and max settings would be a guessing game for calculating the exposure.

This is partially why I no longer recommend such high levels of ND filtering, at least for landscape work. It is often far better to use a less dense ND filter and take multiple exposures that can then be combined in Photoshop for a longer exposure effect. It is much easier to get the exposure correct and the color quality doesn't suffer as much.

It should be possible to give a rough indication to the stops. If that were impossible, they wouldn't be able to say "4 to 11 stops"

Also, 1000x is often not enough to get to 30s in bright light. In order to decrease the effort in stacking (which I do) and the danger of seams appearing, I personally believe the individual exposures should be rather long and 30s is (for me) kind of a sweet spot.

Link | Posted on Feb 22, 2016 at 23:10 UTC
In reply to:

Steve Bingham: I got money says the color doesn't stay neutral.

If it can be corrected with a (or rather a set of) custom colour profile(s) in Lightroom, it would still be worth the money for me.

My high quality fixed BW ND1000 has a warm cast and I think is is fair to expect larger deviations from these VNDs.

Link | Posted on Feb 22, 2016 at 23:06 UTC
In reply to:

makofoto: In the movie industry we had drop-in Grad Filters for decades. Mainly for long telephotos. They tended to be ineffectual but hopefully this will work with wider lenses. Filters behind a lens will change the back focus by something like a third of it's thickness. This doesn't effect long lenses but definitely will effect wide lenses. It will be interesting to see how this issue of physics will be dealt with. The 30.5 mm internal Tiffen filters for my Cooke 18/100 T3.0 lens were ultra thin. http://public.fotki.com/makofoto/work/miscellanous/305mmtiffen.html

Spidermoon: For normal filter thicknesses the backfocus can be so huge that the lens cannot physically focus to infinity - it is always *beyond* infinity. In my modified adapter I had to insert a shim to allow focusing to infinity for wide lenses.

Link | Posted on Feb 12, 2016 at 15:21 UTC
In reply to:

makofoto: In the movie industry we had drop-in Grad Filters for decades. Mainly for long telephotos. They tended to be ineffectual but hopefully this will work with wider lenses. Filters behind a lens will change the back focus by something like a third of it's thickness. This doesn't effect long lenses but definitely will effect wide lenses. It will be interesting to see how this issue of physics will be dealt with. The 30.5 mm internal Tiffen filters for my Cooke 18/100 T3.0 lens were ultra thin. http://public.fotki.com/makofoto/work/miscellanous/305mmtiffen.html

I have made a filter-in-adapter myself and it affects wide angles greatly. Corners and even edges are soft, I assume partly because the angle of incidence for wide angles changes across the frame and the backfocus effect that you mention varies accordingly, but even when trying to focus on the corner, it will never be as sharp as without the filter. Because of these problems, I didn't pursue my idea of manufacturing and selling them. Still using them for myself, though.

Link | Posted on Feb 12, 2016 at 14:01 UTC
In reply to:

KameraFever: Very nice. Now all those wide angled lenses that couldn't take filters before will now be able to take filters.

I've been using my own DIY version of filter-in-adapter on my Nex5 and for wide-angle lenses (the very good Pentax 12-24) the corners/edges are rather soft. If they use thinner filter glass than I, it is possible that they will get better results.
It also affects focus, as a plano-parallel plate so close to the imaging plane tends to do.

Link | Posted on Feb 12, 2016 at 02:53 UTC
On article Roger Cicala investigates accuracy of lens adapters (49 comments in total)
In reply to:

PhotoKhan: I don't get this...

If the only purpose of an adapter (the "pure" ones, not something like Metabones) is to reinstate the original Flange Focal Distance a lens was built to work with, why are they optically-bench-testing them?

The only appropriate testings to be done are mechanical and physical-dimensional ones, ie, how dimensional-accurate (and consistently throughout production output) is a particular adapter.

(I guess that would mean getting some measuring equipment they DON'T have...)

You are right, Khan!
I share your assumption: They are lacking the necessary equipment to check the physical dimensions precisely.

Link | Posted on Oct 3, 2013 at 12:07 UTC
On article Pentax Q7 Review (241 comments in total)
In reply to:

Marvol: I have no axe to grind in this Q review, but after reading the posters below I agree that comparing it to "entry-level ILC" cameras completely misses the point of this camera. Even I can see that the camera is not aimed to compete against other ILCs. It actually makes a big effort to be quite different from these cameras.

> I'd really like DPReview et al to be more flexible and compare the same way a potential buyer would compare, not an engineer.

As an engineer, I politely object to that. That's not how an engineer worth their salt should operate.

Link | Posted on Aug 9, 2013 at 13:16 UTC
In reply to:

Guy McLoughlin: Too many people are trying to equate Micro 4/3 and FF DOF, which is largely missing the point. Equivalent FOV is what it's all about. Same F-stop, same exposure.

Micro 4/3 lenses have a 2 stop disadvantage when it comes to shallow DOF, but most Full Frame shooters aren't shooting EVERY shot wide open because often the DOF is TOO shallow.

i.e. A head-shot where the subject's eyes are in focus but their nose is out of focus is NOT a flattering shot.

I shoot corporate video for a living with Panasonic Micro 4/3 cameras, and most of the time my aperture is between f/2.0 and f/4.0 in order to get usable DOF in my shots. With a FF system I would be shooting at f/4.0 to f/8.0 to get the same DOF.

Unless you have a burning need to shoot EVERY shot at full aperture with your FF camera, the Micro 4/3 DOF difference is generally not an issue.

Now Micro 4/3 shooters have a very fast 85mm FF FOV equivalent with built-in optical stabilization, something none of the FF camera systems have.

> Equivalent FOV is what it's all about. Same F-stop, same exposure.

Misleading. On FT 42.5mm/1.2 on ISO 200 gives same FOV, same DOF and same number of photons per image&time as 85mm/2.4 on ISO 800 on "FF". *That* "is what it's all about".

> have a very fast 85mm FF FOV equivalent

I would not call that "very fast", I'm rather sure I'll call it "very expensive", though.

Link | Posted on Aug 2, 2013 at 14:29 UTC
In reply to:

Pat Cullinan Jr: <quote>should provide the depth-of-field control and low-light image quality on an APS-C DSLR that you'd get using an F2.8 zoom on 35mm full-frame.</quote>

The aperture of a lens is quite independent of the format of the film or sensor. In other words, f/1.8 is f/1.8 whether the lens is placed before an APS-C sensor or a full-frame sensor. The intensity of the light striking the target is the same whether you have a small or a large target. The aperture is a function solely of the focal length and the entrance "pupil" (meaning the diameter of the circle of light you see when you look through the lens from the rear).

I hope everybody understands this, because otherwise you'll be making disadvantageous decisions or doing things wrong.

> The aperture is a function solely of the focal length and the entrance "pupil" (meaning the diameter of the circle of light you see when you look through the lens from the rear).

You mean f-stop. Aperture in optical physics is measured in mm. Sadly in popular photography, the terms have become mangled, so I usually say "aperture diameter" to make it clear that I am not talking about the dimensionless f#.

Link | Posted on Jun 7, 2013 at 13:27 UTC
In reply to:

SunnyFlorida: The Nikkor 35mm F/1.8 sells for $180, the 35mm F/2.0d sells for $270 and can be used in 2 formats, Oly is asking $500 for this???

> The Oly is likely to compare quite well, even vs. FF (could even beat that old 35, at least wide open).

But the 35/2 on "FF" would be stopped down to 3.5 for a fair comparison. (Fair= same angle, same DOF, same number of photons captured per time)

Link | Posted on Nov 15, 2012 at 12:44 UTC
On article Just Posted: Pentax K-30 full review (272 comments in total)
In reply to:

OneGuy: It seems Pentax is applying the age old method of subsidizing the body (hamburger) to make some money off the lenses (french fries).

Being new to the various lens mounts, I'd appreciate a primer (or a reference to one) explaining the various acronyms the dpr readers here are sooo capable of tossing about.

DA are the APS-C lenses that support full metering and AF. You can mount any of the older K-mount (Pentax bayonet) lenses directly, with more or less limited functionality (K, M, A, KAF, DFA, FA, FAJ). You can also attach M42 lenses (with an adapter).
Edit: Forgot the Limited and DA* and possibly others ;)

Link | Posted on Nov 1, 2012 at 01:52 UTC
In reply to:

Rupert Bottomsworth: Why would anyone buy this over a Sony RX100?

Elaka, noise at same output size is almost independent from sensor resolution. If you look at it at 100%, the pic with more MP will be also larger, so the noise appears worse (per pixel noise vs. per image noise).

Link | Posted on Oct 24, 2012 at 09:21 UTC
In reply to:

roy5051: UGLY, UGLY, UGLY! Why on Earth have that bl**dy great lump on the top? Surely it is not beyond the bounds of the designers to build the viewfinder and flash into the body? Looks like it was designed by a committee!!!!!

I think you mean abomination, not abortion.

Link | Posted on Oct 24, 2012 at 09:17 UTC

I hope the rating algorithm will be smart enough to detect mob behaviour and people voting multiple times through different accounts and punish those accordingly.
Also, there are cases where a post was criticised (or praised) a lot and then it turns out that the post was actually correct (or wrong) - would a voting be reversed in such a case? I don't see how it would be done.

Link | Posted on Oct 1, 2012 at 13:38 UTC as 68th comment
On article Photokina 2012: Hasselblad Stand Report (47 comments in total)

So Sony themselves are switching to a normal hot shoe and Hasselblad "inherits" a hot shoe that does not match any of their previous cameras?!
They have enough money to design a crocodile hand grip, but fail to make the flash system compatible with their system?!
Oh boy...

Link | Posted on Sep 20, 2012 at 14:30 UTC as 23rd comment

Right now someone at Sony is seriously mad that they didn't go for the NEX fullframe and instead did the RX1. Ah well, there's always next year.

Link | Posted on Sep 17, 2012 at 19:26 UTC as 116th comment | 1 reply
In reply to:

increments: Given the quality of some of the existing AF wide angle zooms, this is either going to have to be stellar in terms of IQ, or be very affordable...

Is it greedy to want both? ;)

> Sigma 10-20mm £326, Tokina 11-16mm £500, Canon 10-22mm £540, Tamron 10-24mm £350.
> Samyang 14mm £330

The Samyan g is a FF lens. While this is maybe of no relevance to an APS-C user, it does explain some of the price. (Pentax's APS-C 14/2.8 is also more expensive.)

Link | Posted on Sep 14, 2012 at 19:30 UTC
In reply to:

Jan Kritzinger: I can't believe there are people on this forum who say no to f/2.8.
You will always run into situations where you don't have enough light. ALWAYS.

It's nice, but being able to mount a filter and size are also important. I can understand people preferring one over the other.

Link | Posted on Sep 14, 2012 at 14:41 UTC
Total: 71, showing: 1 – 20
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