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Forum: Pentax Price Watch 08-06-2018, 03:27 PM  
$1,953 for A* 135/1.8 (also apparently 12% additional off) at Keh
Posted By jbondo
Replies: 24
Views: 1,290
Like HarisF1, I have both.


Sharpness: Samyang is sharper wide open. Pentax has some CA from f1.8-2.2, and it catches up to the same league about F2.4. From 3.2 up, both are super sharp and well corrected.

Color Rendering: Pentax is better. I don't like the blues of the Samyang. It's a pretty big difference for portraits.

Bokeh: Under some circumstances Pentax bokeh balls make colored outlines. Despite this, the Pentax bokeh is more pleasing.
Transmittance (T-stop): The Pentax passes significantly more light at F2 than the Samyang does at F2. Wide open it handily beats the Samyang in t-stop, making it superior for (non-astro) low light shooting.

Astroprotography: Near wide open, the Samyang has superior color correction from about 420nm on up to the near UV, making it superior for star photos.

Build/feel/usage: Pentax is much heavier. Pentax quality/feel wins by a mile. Also, you may have to try more than one copy of the Samyang to get one that's uniformly sharp in each corner. (my first one wasn't)
Forum: Pentax Camera and Field Accessories 07-18-2018, 06:26 AM  
LIM's SAH-BE52N1 52mm metal hood - anyone use one?
Posted By rogerstg
Replies: 4
Views: 602
The $10 Sensie Pro hood seems like a simpler alternative if you like a metal hood. No adapter required.



I bought two; a 52mm and 49mm along with two 58mm lens caps for my 50mm and 35mm lenses.
Forum: Pentax K-1 06-26-2016, 11:34 PM  
Sigma Damage to K-1
Posted By funktionsfrei
Replies: 36
Views: 4,122
Yes. Usually, they work without problems. I've got two - a 12-24 and a 24-70, both sporting a diaphragm ring (lockable in 'A' position).

You can check yourself - the bayonet ring on the "affected" lenses, that is those with the mechanical problem, ist really huge. Check the image above posted by noelpolar, here you can see the bayonet contacts in relation to the ring's diameter.

Older Sigma lenses used normal-sized bayonet rings (at least the ones I know of), so there's no problem.

The firmware problem (causing camera body lockups) might be related to SDM/HSM lenses only, since the KAF3 protocol clearly is different from the KAF protocol.

From all the Sigma glass I've got only one is problematically, that's the 70-200/2.8 APO EX DG HSM Macro II, and that one's currently being serviced by Sigma.
Forum: Pentax Camera and Field Accessories 12-01-2014, 02:25 PM  
Sigma EF-530 DG ST compatbility
Posted By DeadJohn
Replies: 4
Views: 1,443
I think that quote about firmware updates applies to the 530 (and 610). Very old 530 flashes had firmware that doesn't work properly with the K-5. Newer 530 flashes shipped with newer K-5 friendly firmware. Sigma can update firmware of old flashes but you have to mail the flash to them. Contact Sigma support.
Forum: Pentax SLR Lens Discussion 08-10-2014, 10:35 AM  
Is DXO biased ?
Posted By DominicVII
Replies: 51
Views: 4,814
'Infinite regress' in scholastic philosophy means the the indefinite extension of the chain of causes. According to Schopenhauer, there is nothing wrong in positing infinite regress; as a matter of fact, Schopenhauer is an advocate of infinite regress.

Infinite regress does not follow from the two quotes that you have selected at random:

(x) Is A B? (particular)
(y) No A is ever not-B. (universal)

If you are gonna play philosophical mind games, then do it the right way, or don't do it at all.

People come here with honest questions, and they are met by smug and not-so-clever dialecticians.

I feel like I'm on a DPreview forum. I would have thought that the Pentaxians were better than that.
Forum: Pentax SLR Lens Discussion 06-28-2014, 09:07 AM  
Pentax Prime Lenses vs Canon and Nikon
Posted By normhead
Replies: 101
Views: 10,073
It gets really tiring people talking about Canon and Nikon shooters using systems that cost 4 times what Pentax does, making arguments like this. Everyone on this site knows Canon and Nikon make more expensive, more pro-friendly systems, and sells more cameras than Pentax does. That is not a credible argument in terms of adding something to the conversation... they may or may not-compete with Pentax's level, at their level, but you didn't really add to our knowledge of that, issue.

Have you any idea if you hang around here for a while of hearing lines like


Not one person here, has into brought that logic in their purchasing preferences, or we'd all own Canons or Nikons. We are a bunch of people who look beyond statistical trends in our purchasing decisions to see what we can get for our money. That is the last argument you should use on this site to make a point. We already know you're wrong. Who sells the most cameras does not indicate who makes the best cameras, on any single given issue, including WR.
Forum: Pentax SLR Lens Discussion 02-16-2014, 06:42 PM  
Revisiting the HD DA 20-40mm Limited
Posted By Uluru
Replies: 53
Views: 8,562
The only difference between a good lens, and a bad lens, is in time allowed to understand it and pull out our maximum of knowledge and possibilities about it. Whoever thinks that a good lens should in general provide a 100% of keepers and utterly magnificent photograph each time shutter is pressed, is seriously deluded.

Old rule was 1 good frame in 3 rolls of film, and the preference was always given to the subject and the narrative over the mere technical quality of the best overall image. Even if the lens is technically mastered and understood, the hard part still remains, every single time: to make that what fits inside the frame lines worth capturing, and ourselves capable of doing it.

Many confuse the two, the lens and its subject, and find excuses for the latter in the realm of the former. So no wonder many famous photographers used just one or two lenses, that made them famous. However, many totally forget about the lens inside their mind: less time they had spent on understanding the lens on the camera, more time was left to dedicate to subjects.
Forum: Pentax SLR Lens Discussion 02-04-2014, 07:15 AM  
Zooming with your feet, will new zooms end that?
Posted By Ishpuini
Replies: 53
Views: 4,365
Exactly, it has everything to do with the photographer and nothing with the gear as such. And also a bit with what circumstances allow.

I do believe that most people start as "lazy photographers". Partly because of the ease of a zoom. This is the reason why most photography schools I know of (including the one where I took my photography degree) request first year students to use a standard prime for all assignments. My teacher verified focal length in the EXIF and refused to even review images with too short or too long a focal length, let alone accept them. A full year of not having zoom flexibility ingrains a compositional approach that removes most people's seemingly innate reflex to zoom first. Though there are always students for whom this approach doesn't work at all...

Once that hurdle is taken by a learning photographer it comes down to discipline and what circumstances allow indeed. However, I observed many (if not most) fellow students revert to substandard compositions when they were allowed to use their zoom again from the second year on. Which is what I meant by zooms make lazy photographers: these students stopped moving once they felt they didn't "have to" anymore. Of course, that's because they never really understood why they got better results by moving around. The students that kept their hands off the zoom ring when framing and only used it when subsequently cropping, ended up being the ones that made it through the four years and got the degree. Most others dropped out before the end of the second year, frustrated with their inability to grow in their photography.

However, had these dropouts used a limited zoom such as the DA20-40 instead of their then fashionable 18-200 style zooms, perhaps this "limitation" might have given them the extra time for the required realization. As such these particular "new" zooms with limited range make a difference that is not necessarily IQ related.

It's not the gear's fault of course, nor is this observation in any way related to a (non existing I agree) limitation of zooms. That was in no way what I wanted to imply.

Wim
Forum: Pentax SLR Lens Discussion 02-04-2014, 04:30 AM  
Zooming with your feet, will new zooms end that?
Posted By Ishpuini
Replies: 53
Views: 4,365
Of course, zooming by changing focal length is not the same as zooming with your feet. When you move in relation to your subject in order to frame it, perspective changes. When you change focal length and remain on the exact same position relative to your subject, perspective does not change.

IMHO zooms do make lazy photographers. I.e. a zoom makes it easy to fit a subject into the camera's frame. Now, this is not the same as framing an subject for an image. The former is a 2D crop operation, the latter a 3D composition effort. When you wish to include a subjects relation to foreground and background as compositional elements, "zooming" with your feet is essential, regardless of the lens you have on camera.

However, after having determined the 3D composition of a shot, a zoom does make it easier to crop exactly the envisioned shot, without requiring a change of lens.

Recent zoom lenses with limited focal range such as the Sig 18-35 or the DA20-40 may indeed change things. For me the DA20-40 does in any case. It's range is sufficiently limited to ensure my not becoming lazy and just zooming to get a subject. It's not wide/long enough for that. Hence I still have to move to get the subject nicely framed in relation to its foreground and background, and the 10mm I can zoom in or out from its "standard" position at 30mm allow me to crop more accurately than I might when shooting a standard prime such as the FA31/1.8.

It's not really an IQ issue to me. It hasn't been for many years to be honest. It's always been a choice between convenience and flexibility on one hand (for zooms) and slow photography (when selecting primes). I feel that a lens like the DA20-40 offers both.

Wim
Forum: Photographic Technique 09-05-2012, 08:37 PM  
Places to visit and photograph in Montreal?
Posted By bobmaxja
Replies: 7
Views: 1,686
I live here
Old montreal for sure because of the architecture, the mountain for the nature and Montreal view, McGill university campus, Olympic Park for futuristic look, Botanical garden, the hundred church in the city + the Cathedral and the Oritory. You can also visit some area in Westmount upscale . The underground Metro should be good but could be touchy ,
Other area , the different bridge, Place Ville-Marie, the cemetery on the mountainis huge and the nice girl
Forum: Photographic Technique 09-06-2012, 08:42 AM  
Places to visit and photograph in Montreal?
Posted By Thesorus
Replies: 7
Views: 1,686
Old Montreal/Old Port : good for old building; river side, boats, walk up west towards the Canal Lachine; you could go to Ile St-Hélene to the Place de l'Homme for a view of Montreal from across the river

Marché Jean-Talon: Farmers' Market, especially on weekends; there might still be flowers, but there will be tons of people and vegetable stands .. much fun!

Boulevard St-Laurent: From Old Montreal up to Marché Jean-Talon (long walk, but fun)

Subway: Can be fun, some of the stations are really nice (they all have different architecture), but you will have to stay inside).

The Mountain : Nice walk up the Olmstead path to the Belvedère for a nice view of Montreal downtown area

Plateau/Mile-end Area for a nice urban feel.
Have a look at side-streets and alley-ways, especially the ones that were transformed into gardens (À propos | RUELLE VERTE)

For "macro", have a look at the botanical garden, and ride up the Olympic stadium tower for a nice view of Montreal from a different angle.

Some of my flickr sets that can inspire you :

Ruelles 31 juillet 2010 - a set on Flickr
Montréalités juillet 2010 - a set on Flickr
Pérégrinations printemps 2010 - a set on Flickr
Montrealités 11 octobre 2009 - a set on Flickr
Forum: Pentax SLR Lens Discussion 08-01-2012, 08:56 AM  
A close-focusing, fast 28mm shootout: Sigma 28/1.8 vs Vivitar 28/2
Posted By Erik
Replies: 6
Views: 4,789
I just found this little Vivitar in a second-hand shop, picked it up, and immediately thought to compare it to my Sigma 28/1.8 which I use all the time. According to the bestiary, this is a Komine-made model. So yeah, let's see what we've got:

The contestants:



Vivitar 28mm 1:2.0 MC Close Focus Wide Angle
8 elements in 7 groups
Minimum focusing distance: 23 cm
Maximum magnification: 1:5
Aperture: 6 blades, f/2-f/16
Filter size: 49 mm
Weight: 280 g

Sigma 28mm 1:1.8 EX DG
10 elements in 9 groups
Minimum focusing distance: 20 cm
Maximum magnification: 1:2.9
Aperture: 9 blades, f/1.8-f/22
Filter size: 77 mm
Weight: 500 g

Now, obviously, the Sigma is a modern lens with "A" mode on the aperture ring as well as autofocus, and is therefore quite a bit more convenient to use on a modern camera. It also focuses closer. However, it is a lot bigger and heavier than the Vivitar! Not only that, but seeing as there are few (inexpensive) options for fast lenses in the 28 mm range, and given how useful this focal range is as a walk-around lens on an APS-C DSLR -- especially when the lens does close-focus -- the Vivitar could be potentially interesting for many Pentax DSLR owners.

All these pictures were shot on a K-5 on a tripod, manually focused in zoomed-in LV mode. RAW processed in Lightroom, default settings. No attempt made to correct exposure. The shutter speed was the same for a given aperture with both lenses.

Brick wall series (sharpness test):

Sigma:
f/1.8
f/2
f/2.8
f/4
f/5.6
f/8
f/11

Vivitar:
f/2
f/2.8
f/4
f/5.6
f/8
f/11

As uninteresting as brick walls are, here they allow us to note a couple of things right away:
  • While both lenses are nominally 28mm, the Sigma has a slightly wider field of view.

  • The Vivitar seems to let in slightly more light at the same shutter speed and aperture, i.e. exposes brighter.

  • The Sigma has slightly more contrast and seems to render colours a bit warmer, but beware that the differing exposures exaggerates this effect. Equalize the exposures and they're much closer.

  • The Vivitar is visibly sharper in the corners, right up to about f/8. In the center, I find they're pretty much equal.



Close-focus/bokeh test:
In this test, I focused the Vivitar to its absolute closest point and then adjusted the Sigma to match. The focus point looks to be a bit further back on the Sigma. Sorry about that. Remember that the Sigma CAN focus quite a bit closer than this, but I wanted to level the playing field.

Vivitar:
f/2
f/2.8
f/5.6

Sigma:
f/2
f/2.8
f/5.6
  • Again, we can see that the Vivitar lets in a little bit more light and has a different field of view -- the camera was not moved between the lens change.

  • The bokeh on the Vivitar is a little busy (check out the "KR-10" writing in the f/2 sample) owing to the mere 6 aperture blades. The Sigma is smoother with its 9 blades.

  • I much prefer the calmer rendering of the Sigma in the f/2 image. Already by f/2.8, I don't really have a clear preference.

  • Both lenses display a little CA/PF. It is not really a big deal and gone by f/5.6.


So, a conclusion from this very unscientific test? Well, draw your own, if you want. The Sigma has better bokeh and focuses quite a bit closer, but the Vivitar is actually slightly sharper overall. If I had to sell one of these I would keep the Sigma, but the Vivitar seems to be a great lens for its size and price. I got it for $65 with a Ricoh KR-10, a Rikenon 50/2, Soligor C/D 80-200, bag and flash. :lol:

EDIT: Oh yeah. The Sigma had a Hoya UV filter on, the Vivitar nothing. So keep that in mind. It didn't even occur to me until right now.
Forum: Pentax SLR Lens Discussion 07-16-2012, 10:09 PM  
SMC-M Pentax 50mm f/1.7 Not Sharp
Posted By séamuis
Replies: 24
Views: 3,057
the first part of your post makes no sense. You answered your own question. As to the lens, eveyone here seems to forget or haven thought (especially the op) about the fact that we are talking about used vintage lenses, that have an unknown history. so blaming the an entire series for one lenses poor performance is just nonsense. The M 1.7, like virtually all pentax 50-55mm lenses gives excellent performance, even wide open. But then virtually all such lenses, no matter who manufactured them perform well, as they are all based on the same few basic optical formulas. If your particular example is performing poorly (or worse than you assume it should) and you are sure its not the film, the development, the camera or the scanner, then the lens is certainly to blame, but not all M series, or 1.7's or 50mm's. Just your lens.

Since we dont know the history of the lens, its hard to say. The most probable culprit is something like an element isnt in properly, or it wasnt reassmbled properly at some point. Such as an element put in backwards or something similar.
Forum: General Talk 06-25-2012, 09:55 AM  
Any suggestions on how to make new friends in a new place?
Posted By reeftool
Replies: 15
Views: 1,712
I repair truck and trailer refrigeration equipment. It has provided me and my family with a solid, stable, and secure source of income for many years. My wife is a nurse and works with medically frail and severely handicapped people. There are 2 choices in my field and I have worked both. For 20 years, I worked for a dealership. An 8-5 dayshift. It was also a small business with poor benefits and often after hours callouts which interfered with family life. I currently work for a private fleet/foodservice company. The trucks are rolling all day and must be repaired in the hours before the next days deliverys. This job has good benefits, top pay, pension, etc, all you would expect from a large corporation but really crappy hours. It's always been a trade off. It has not always been easy but we have managed to hang in there as a family. We went to the school plays, the sporting competitions, the graduations and usually without any sleep. The kids are through college and grown and we have enough saved where retirement is possible. A lot of folks won't work my hours. We have been short handed for some time, a 50K a year job nobody wants.

When you go to the store to shop, stop at the diner to eat, remember that a lot of people worked all night so you can enjoy those conveniences. The sick are cared for all night and there are no holidays. All the food you stuff your faces with on the Fourth of July were delivered by folks who drove all night on trucks that were loaded all night. It never stops, 7 days every week. Making new friends isn't easy. I stopped worrying about it years ago.
Forum: Pentax SLR Lens Discussion 08-26-2011, 10:47 AM  
is this one and the same lens?
Posted By Just1MoreDave
Replies: 14
Views: 1,890
I don't know a lot about metal, but I'll say you guys are wrong anyway. This is the inside of four loose mounts I have at the moment, some Pentax, some third-party K, various ages:



And the metal mount from an SF1:

Forum: Pentax SLR Lens Discussion 05-11-2011, 01:22 PM  
FA VS D FA 100mm macro comparison
Posted By axl
Replies: 26
Views: 7,960
there is couple of differences between F/FA/DFA and DFA WR macros.
to start of it's clamp and limiter:
F - limiter no clamp
FA - limiter and clamp
DFA - clamp only
DFA WR - no clamp no limiter

the clam is semi useful IMO, but limiter is great thing to have, you can either have 0.303 - 0.7m or 0.7 - infinity limited focus range, or full 0.303 - infinity focus range. If you are not using this lens a macro exclusively it's VERY useful.

Next thing up is build, F has metal barrel and semi plastic outer shell I believe. FA has metal barrel and metal shell, DFA is just about all plastic with exception of mount and DFA WR has metal shell and plastic barrel. Filter ring is 58mm on F and FA and 49mm on DFA and DFA WR.
Optical layout is the same, but in F and FA the outer shell is much bigger and front element is recessed deeply into the lens body. As consequence these two don't come with hood. The recession is not deep enough for all purposes so sometime extra screw in hood would be handy but it remains constant (the front element is recessed into the inner barrel) so even with 1:1 magnification the front element is somewhat shielded. On the other side, the hood of DFA and DFA WR is fixed on the outer shell and does not extent with the inner barrel (f.e. like with Sigma 105) so when the lens in at 1:1 magnification the front element is nearly at the level with the hood.
The WR version offers rounded blades and WR of course, but both F and FA versions focus quite a bit faster then both DFA versions.
And as Pentaxor wrote, the FA versions has very characteristic FA way of rendering colours which is quite different form DA/DFA series of lenses.
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