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Forum: Pentax SLR Lens Discussion 10-15-2017, 11:15 AM  
Someone here who's still using the oldest sigma 70-200 (APO EX (1999)) ?
Posted By Lowell Goudge
Replies: 12
Views: 662
I have this lens, bought it with my *istD and have continued using it with the sigma 1.4x and 2x teleconverters with great success all the way up to my current k5 / k7 body pairs.

When the DG Marco came out there were a lot of complaints that the DG macro was soft wide open at 200mm , not so with the original.

I wouldn't trade it for the world.
Forum: Post Your Photos! 09-18-2017, 06:26 AM  
Misc Not for me thanks
Posted By Lowell Goudge
Replies: 5
Views: 418
perhaps it is a statement about the water quality in the canal?
Forum: Lens Sample Photo Archive 09-16-2017, 01:11 PM  
Pentax D-FA 15-30 f/2.8 ED SDM WR Samples
Posted By Lowell Goudge
Replies: 4
Views: 549
sadly now we have 2 threads for this lens.

please refer to the index before creating a new thread in the future
Forum: Product Suggestions and Feedback 09-07-2017, 11:25 AM  
Wildlife Photographers: DFA or DA 400mm 5.6
Posted By Lowell Goudge
Replies: 35
Views: 1,661
what version of the tammy do you have. i tested one many years ago, with the 1.7x converter and my K10 at the time but the one i tested had terrible fringing in the red spectrum and some lateral CA, when focused on a black and white sign. More than what i can recall from my K300/4 and 1.7x which i admit does have some. but i think there was a 60A, 60B and 360 versions.

the 60A did not consider the UV filter in the optical path and performed worse with it when installed, the 60B corrected this issue, but the 360 is I think the one to really look our for but they are rare.
Forum: Product Suggestions and Feedback 09-07-2017, 07:28 AM  
Wildlife Photographers: DFA or DA 400mm 5.6
Posted By Lowell Goudge
Replies: 35
Views: 1,661
for me, i look at weight for this solution.

while a zoom is a nice to have, you generally are at the maximum focal length all the time,

therefore if i look at what i have presently in this focal length range, and autofocus, i have a sigma APO EX 70-200/2.8 (non DG NON MCRO) plus 2 x TC with a combined weight of about 1850 grams, or the K300/4 plusa 1.7x converter at about 1100 grams .

i would expect a DA/DFA 400/5.6 at an equivalent weight to the existing FA of 1140 grams or perhaps lighter .

while a DFA is probably not an issue with compatibility or even optical design, it is less attractive for wild life users on FF since even at 400 mm there is a lot of cropping on an APSC sensor

me personally i would like something longer, at F5.6 or faster. but at the moment all there is is the DA 560/5.6 for me that is the next logical step, or perhaps the sigma 500/4.5 with a 1.4X
Forum: Pentax SLR Lens Discussion 08-21-2017, 01:23 PM  
Overview of all historical Pentax PK and M42 lens makers/brands
Posted By Lowell Goudge
Replies: 9
Views: 732
sadly the list is under stated, there are, for example over 30 vivitar 28mm varients yet i only see about 8

but it is a start
Forum: Pentax SLR Lens Discussion 08-18-2017, 02:35 PM  
determining the focal length a Teleconverter will support?
Posted By Lowell Goudge
Replies: 7
Views: 767
Ff aside from evolution of mounts from PK to PKA ' to PKF, and compatibily and functionality, there is no unsupported focal length.

What there is however is that for AF to work, you need a native open aperture of the TC and lens to be less than F6.7 (this might be F8 on newer bodies

There are also some Pentax and sigma teleconverters with protruding front elements that only work on a select few lenses,
Forum: General Photography 08-17-2017, 03:37 AM  
Is your car a public or private place?
Posted By Lowell Goudge
Replies: 65
Views: 1,890
I believe that the real question based on what I understand the privacy laws are in canada, is how much effort is required to take the picture.

The reason I say this is that even considering the vehicle as a private space, it is somewhat like taking a picture through a store window, or into someone's yard from the street. If the shot is something that can be seen with the naked eye, then it is not an invasion of privacy because it is in plain view. If you need something special, like an unreasonable vantage point offered by climbing a pole, ladder etc, or an unrealistically long telephoto lens to get the image from far away etc, then it is invasion of privacy. This is how the privacy laws have been applied to the tabloid press with celebrities .

This situation from the privacy aspect is probably legal , but what will you do with the photo? You cannot sell it without a release because the people are clearly identifiable and the principle subject"

Then you have the other issue, that while in control of a motor vehicle you are clearly not paying attention to what is arround you, if you were off the road, in park, etc, it is one thing but in the middle of traffic it is quite another.
Forum: Product Suggestions and Feedback 08-15-2017, 03:28 AM  
Focal Length Setting
Posted By Lowell Goudge
Replies: 20
Views: 943
All I was eluding to is that within the lens standards, such as they are, there are tolerances allowed for not only focal length but maximum aperture as well, and that the makers have some freedom to advertise the lenses somewhat as they wish.

In the past, when photo magazines were free (or seemingly independent enough to report this data) it was not common in a lens report to provide the maximum aperture and focal length of the sample tested. Try out the lenses, you may get a surprise.
Forum: Product Suggestions and Feedback 08-14-2017, 05:11 PM  
Focal Length Setting
Posted By Lowell Goudge
Replies: 20
Views: 943
As I am ever the sceptic, the two lenses are probably identical just marked differently to allow one maker to have bragging rights .

Look at the samyang lens line up, the 14/2.8 is marked 13mm by only vivitar. But all the lenses, vivitar, bower, samyang Robinson etc are identical optically
Forum: Post Your Photos! 08-14-2017, 04:28 AM  
Machinery A New One on Me
Posted By Lowell Goudge
Replies: 10
Views: 403
I always liked the 1800es and the P1800 generally.

I think the Jensen looks like the 1800es not because of the designer, but more that at the time this car was made, automakers had begun using frameless rear Windows in general. Remember the AMC pacer. The Jensen, the 1800es and the pacer all share one common thread. A lot of glass,

Aside from this, there is not really anything similar in the lines of the cars, at least when I go back and look at the photos of the 1800es and clearly the pacer was completely different
Forum: Pentax SLR Lens Discussion 08-14-2017, 04:21 AM  
Question about Depth-of-field & focal length relation
Posted By Lowell Goudge
Replies: 23
Views: 1,182
You need to go back to basics.

Depth of field is based upon the definition of what is acceptably sharp. This all goes back to the film era where the common print format was an 8" X 10" print.

Acceptably sharp was considered when a point source still appeared to be less than 1/100 of an inch. When looking at a 35mm negative blown up to fill the 8" X 10" format.


It all relates to this definition, and to the amount of magnification in your processing. If you enlarge beyond the 8x10 print size depth of field goes down.

Overall you need to consider the full magnification subject through lens, to sensor then enlarged to print.

Play with any of the DOF calculators on line and you will see the relationships form.

Subject distance , lens and sensor size are all in the equation, (but they seem to always omit the print size) but if you brake it down, you will soon see that in the end focal length, distance and sensor size (assuming you fill the sensor with the image) really only come back to the magnification of the system.

What depth of field calculators do not do, is give you any idea of the rendering of the out of focus area or bokeh. This is far more important that depth of field on its own, and generally is "nicer" with longer focal lengths, because the out of focus points appear as big blobs, compared to small circles (or what ever shape your aperture is)

Also consider when shooting portraits, it is as important to control the subject to background distance and background pattern as it is to control depth of field
Forum: Pentax SLR Lens Discussion 08-13-2017, 04:40 AM  
Getting Asahi Pentax Spotmatic in 2017?
Posted By Lowell Goudge
Replies: 17
Views: 926
I would bypass all the m42 and k mount MF bodies and get a PZ-1 or PZ-1p (or Z-1 / Z-1p away from North America)

They can use all but HSM lenses have excellent metering, work with MF lenses just like any K or M body , has some great exposure features and 1/250 flash sync

If the OP is a pro,Mathis is a way to lead him into digital as wall with Pentax.
Forum: Lens Sample Photo Archive 08-12-2017, 12:06 PM  
Carl Zeiss Distagon 21mm f/2.8
Posted By Lowell Goudge
Replies: 4
Views: 593
thats ok i made this thread the active link since the ther one had all the photos disappear
Forum: Lens Sample Photo Archive 08-11-2017, 04:32 AM  
Carl Zeiss Distagon 21mm f/2.8
Posted By Lowell Goudge
Replies: 4
Views: 593
They were here , CZ Distagon T* 21 ZK - PentaxForums.com but sadly almost all images are gon probably due to photobucket
Forum: Troubleshooting and Beginner Help 08-03-2017, 05:17 AM  
Av mode with M42 lens
Posted By Lowell Goudge
Replies: 8
Views: 454
yes

not quite, in the *istD series it worked in all modes, but starting in the K series it was not useable in manual mode, even though there are some valid reasons why you would want it, it is not possible

not quite. with K & M series lenses i.e. no A setting on the lens, av mode shoots wide open regardless of where the aperture ring is set, but it meters based on light through the lens.\\with M42 lenses, if you use them stopped down, it meters based on the light coming through so it does work.

with the K10D for the OP, please note that the metering is only accurate if the aperture is set to F5.6, below F5.6 it tends to under expose, nd this can be in excess of a stop at F2 and below. and it over exposes by 1-2 stops at F8-F11, before falling back to about +.5 over exposed at F32.

K10 metering with manual lenses has been a long discussed topic.

metering improves greatly if you get the origonal focusing screen out of an *istD
Forum: Pentax SLR Lens Discussion 08-02-2017, 04:36 AM  
Odd exposure behaviour with Tamron 10-24 on K-3?
Posted By Lowell Goudge
Replies: 10
Views: 502
The lens is a variable aperture, it may be that any variation in aperture between f3.5 and f5.6 is assumed to be wide open and driven totally by focal length.

Try changing the zoom. Just a thought,
Forum: Pentax SLR Lens Discussion 08-01-2017, 06:51 AM  
Odd exposure behaviour with Tamron 10-24 on K-3?
Posted By Lowell Goudge
Replies: 10
Views: 502
not the same lens but same issue from tamron, their 28-785 XR Di F2.8 zoom also suffers from exposure drift, under exposing wide open to over exposing fully stopped down it is almost linear in behavior, with only F5.6 actually being correct.

edit note, i test a lot of my lenses for exposure across aperture range by focusing on a uniformly lit cement block wall (back of my house which faces south.)

it is good practice for anyone getting a new lens to check out the metering. everyone spends so much time on focus compensation, but no one looks at metering behavior
Forum: Pentax SLR Lens Discussion 08-01-2017, 06:42 AM  
Poll: If only limited to one Pentax vintage lens series which would you choose ?
Posted By Lowell Goudge
Replies: 37
Views: 1,773
you need to widen the M42 takumars out a little, there are presets, super tak's, and SMC Taks as a minimum. personally i like the preset taks because of the bokeh.

in k mounts i like the SMC Pentax (AKA K series) build and finish seem superior over the later M and A series
Forum: Pentax DSLR Discussion 08-01-2017, 06:38 AM  
Why has no camera maker done this..?
Posted By Lowell Goudge
Replies: 40
Views: 2,426
just to be clear, the storage on phones, specifically apple devices is fixed for a simple reason, apple is in the business of selling streaming media and copy protected media (songs and movies) , removable storage was never considered because it makes it hard to control the distribution of media. the down side is that the media has a wear out life (write cycles before failure), and continual writing to the same media would lead to wear out. especial in the File Allocation Table area. when you consider a camera, do you want it to tunr into junk due to a memory failure? how many people here have written in about memory card failures, do you want that to propagate to blame the maker of the camera
Forum: Pentax SLR Lens Discussion 07-31-2017, 05:03 AM  
Lenses Explained, Please
Posted By Lowell Goudge
Replies: 17
Views: 1,079
just to answer directly the question

pentax like sigma and tamron (and i am sure also the other camera makers use codes to explain the range of lenses, and formats.

considering only autofocus, for pentax.

FA are full frame film era lenses, sigma and tamron had no specific designations
DFA are revisions of the full frame film lenses with coatings to reduce internal reflections specifically off the rear element, they are similar to Sigma DG lenses or Tamron Di lenses
DA lenses are lenses specifically designed by pentax for cropped sensor bodies, Similar to sigma DC and Tamron Dii lenses

quality is a question that is not answered directly by the lens coding and you need to consider other things as well.
Forum: Pentax SLR Lens Discussion 07-27-2017, 12:57 PM  
WR Travel Lens(es) For K1? Pentax-D FA 24-70mm Or Recommend Something Else?
Posted By Lowell Goudge
Replies: 21
Views: 1,287
I don't get it, you want WR but are looking for fast and wide to shoot indoors, if you are indoors, what is the issue with changing lenses? Am I missing something?

For fast and spwide, I know it is not WR or AF but what about a samyang 14mmF2.8
Forum: Pentax SLR Lens Discussion 07-24-2017, 09:31 AM  
Sigma 70-200mm F2.8 APO EX or SMC Pentax FA* 80-200mm f2.8 ED ?
Posted By Lowell Goudge
Replies: 18
Views: 1,085
i was referring to the point that latest lens designs were not always superior, using the sigma 70-200/2.8 as the example, it was not a case of looking myself for a new lens, i am quite satisfied with the sigma thank you. and i would put the sigma 70-200/2.8 EX plus their 2x teleconverter against the bigma any day of the week.
Forum: Post Your Photos! 07-21-2017, 04:22 PM  
People Shoreside Sirens Mum
Posted By Lowell Goudge
Replies: 6
Views: 510
It is not a question of believing, it is a question of how gullible tourists are. The truth is secondary to making tourists believe
Forum: Post Your Photos! 07-19-2017, 06:00 PM  
People Shoreside Sirens Mum
Posted By Lowell Goudge
Replies: 6
Views: 510
I think the Scott's treat Nessie like Canadians propagate the myth that anything north of Buffalo is a frozen wasteland.

There is a national obligation to reinforce these myths to the rest of the world and tourists are fair game:D
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