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Forum: Digital Processing, Software, and Printing 17 Hours Ago  
Gimp 2.10 "Color to Gray"
Posted By GUB
Replies: 3
Views: 343
Color to gray with aggressive settings and replacing the V channel of a HSV decompose of the original color image.
Forum: Pentax SLR Lens Discussion 17 Hours Ago  
'Fudging' aperture numbers
Posted By GUB
Replies: 26
Views: 972
Yes the M135 wide open is slightly back focused but going by the cracks in the timber only by an inch or two. (The other two caps are about 500mm forward and back of the centre one). May be enough oof to upset the result but certainly not enough to change the focal length calculation. Note that the Tak m42s share the fov of the M135.
In other comparisons with my M135 it has fallen short of the Taks in sharpness. Mine might be a poor example.

Testing old glass out at infinity is not a good option as many have slipped out of adjustment (or never were in) and won't reach infinity without adjustment.
Forum: Digital Processing, Software, and Printing 22 Hours Ago  
Gimp 2.10 "Color to Gray"
Posted By GUB
Replies: 3
Views: 343
If I understood the settings better it would be nice to not have the shadow halo around her.
Forum: Pentax K-1 23 Hours Ago  
Pancake Lenses on K-1 Mark ii
Posted By GUB
Replies: 24
Views: 699
In the dog picture the seam on the bedding bottom right right drops out of focus in the right hand corner. that is the sharp focus drop-off I noticed on FF.
Forum: Digital Processing, Software, and Printing 1 Day Ago  
Gimp 2.10 "Color to Gray"
Posted By GUB
Replies: 3
Views: 343
Does anyone use this function much? There is not much on line about it.
Usually I am not into effects - preferring a lifelike feel instead but this effect can put a bit of zing into a B&W that is otherwise a little boring.
All images courtesy of the K1
The "Bridge to Nowhere" shot is a hybrid of "color to gray" and simple "de-saturate" where the effect is too overpowering. Mainly "de-saturate" in corners.
The church is a night shot.
Things look a little over-sharp here but the print up a treat on rag paper.
The grain is a product of the process.
Forum: Pentax K-1 1 Day Ago  
Pancake Lenses on K-1 Mark ii
Posted By GUB
Replies: 24
Views: 699
Well there is this thread -- Is the 40mm 2.8 Pancake really that bad? - PentaxForums.com
From memory the take home from it was the DA 40 2.8 XS has severe sharpness drop off on the corners on full frame. And I understand the XS to be the same optics as the limiteds.
Forum: Pentax SLR Lens Discussion 3 Days Ago  
'Fudging' aperture numbers
Posted By GUB
Replies: 26
Views: 972
And I did a quick measure up over here--
The poor old much maligned Takumar Bayonet group. - PentaxForums.com
(Post 13)
At 6 metres the Takumar Bayonet 135 2.5 was 94% of the focal length of the M135 3.5 ie 128mm
Forum: Pentax SLR Lens Discussion 4 Days Ago  
5 Lens Comparison @ 28mm using Evening Architecture Composition
Posted By GUB
Replies: 14
Views: 984
Because when something is so good you just can't say no!
This is approx US$20 delivered.
Forum: Pentax SLR Lens Discussion 02-07-2020, 08:10 AM  
5 Lens Comparison @ 28mm using Evening Architecture Composition
Posted By GUB
Replies: 14
Views: 984
I see it as the Mk1 M28 being the low flyer and the others pretty similar.
Forum: Pentax SLR Lens Discussion 02-07-2020, 08:08 AM  
5 Lens Comparison @ 28mm using Evening Architecture Composition
Posted By GUB
Replies: 14
Views: 984
Yes I would have thought so too but whenever I happen to test a few identical model lenses together they perform very similarly. I am off for a week but when I get back I will do a comparison of my 4 Takumar Bayonets 28 2.8. I have always suspected the Tak Bayonet line to have a lot of quality control issues which would explain the highly polarised opinion of them.
Forum: Lens Sample Photo Archive 02-06-2020, 04:58 PM  
Auto Chinon MCM 55mm f1.7 Macro (M42)
Posted By GUB
Replies: 35
Views: 629
Yep I have got one - images scattered around here mainly in the bokeh thread.
Mine has lost its iris so I replaced it with a black rubber washer that comes out about f2.
Very flamboyant bokeh.



Forum: Pentax SLR Lens Discussion 02-06-2020, 01:47 AM  
5 Lens Comparison @ 28mm using Evening Architecture Composition
Posted By GUB
Replies: 14
Views: 984
And this thread sent me out to compare my Pentax 28mm 2.8s.
Looks like the 1st generation M28 is a low flyer.
And as I suspected the Tak bayonet can hold its own.
The lens caps are my standard test. placed 100x the focal length from the camera.
One forward and one back from the centre one to show missfocus.
Forum: Pentax SLR Lens Discussion 02-06-2020, 01:07 AM  
5 Lens Comparison @ 28mm using Evening Architecture Composition
Posted By GUB
Replies: 14
Views: 984
Aaaaaaargghh my head is turning to mush!!! Need sentences like this to remind me why I shoot in M mode:lol:
The other thing is, after setting up with all at manual settings, to save as jpg to standardise results.
Forum: Pentax SLR Lens Discussion 02-06-2020, 12:58 AM  
Takumar and Vivitar 135mm lenses from Goodwill
Posted By GUB
Replies: 11
Views: 495
Both are good lenses. The Takumar bayonets get bad press but most don't deserve it. I suspect there might have been a lot of sample variation.
I have both and both are keepers.
Forum: Pentax SLR Lens Discussion 02-05-2020, 07:59 PM  
The Bokeh Club
Posted By GUB
Replies: 17,871
Views: 1,597,877
Enna Munchen Tele-ennalyt 240mm 4.5 @f4.5 probably early 60s
Quite good IQ
Despite it being almost archaic it may well go trekking with me. It weighs with hood a mere 330g. Not bad for 240mm.
Forum: Pentax SLR Lens Discussion 02-05-2020, 05:38 PM  
The Bokeh Club
Posted By GUB
Replies: 17,871
Views: 1,597,877
This site says the third digit on the serial is the year - my one is 9 so I would say 1979. Great review for a 40 year old!
Vivitar Auto Macro 55mm f/2.8 Vintage Lens Review | ePHOTOzine
Hopefully Riley will keep on his habit of testing old glass.
The exif on the shot says "m42" so I am thinking I might have attributed wrongly - I have a 55mm fujinon 3.5 that is m42 mt and might deserve the credit:o
The shot was 3-4 months ago. The Fujinon rarely goes for walkies - too many lenses too little time!
Forum: Pentax SLR Lens Discussion 02-05-2020, 01:58 PM  
5 Lens Comparison @ 28mm using Evening Architecture Composition
Posted By GUB
Replies: 14
Views: 984
But given that the Contax image is pretty well a stop brighter than the PentaxM that means the T stop for the M is 2 stops slower than the Contax. That is simply not believable. I am guessing the Contax was wide open - check that the iris is responding when you take a shot.
Forum: Pentax SLR Lens Discussion 02-05-2020, 03:14 AM  
The Bokeh Club
Posted By GUB
Replies: 17,871
Views: 1,597,877
Fly catcher
1970s? Vivitar 55mm 2.8 macro K mount.
Forum: Pentax SLR Lens Discussion 02-05-2020, 03:04 AM  
5 Lens Comparison @ 28mm using Evening Architecture Composition
Posted By GUB
Replies: 14
Views: 984
If that is 15sec and 6 sec rather than 1/15 and 1/6 then Contax has the worse T stop.
Nice subject matter for the comparison but I suspect most of the variation between the shots is the camera varying it's settings. You need to be on M mode with nothing set to auto and then the slower lens shows itself up. i suspect the lighting differences would disappear too.
Also best to test the lenses wide open - stopping them down diminishes the differences.
Which M28 2.8 ? Does it have the chrome ring on the outer edge of the focus ring? (early one) There is quite a reputation difference between the early and later one.
Forum: Photographic Technique 02-02-2020, 06:27 PM  
Photography's Triangle
Posted By GUB
Replies: 99
Views: 2,580
Just to clarify - it is not actually affecting her face, but our viewing eye seeing the two bright areas there and they affect us.
Forum: Photographic Technique 02-02-2020, 05:20 PM  
Photography's Triangle
Posted By GUB
Replies: 99
Views: 2,580
I just downloaded into Gimp and yes the top of the forehead is just at clipping. (I say just at because I never got a dropper value with 100 in all channels.)
I know this is not a critique post but try cloning out the green bokeh in front off her face. Doing so calms the sense of brightness in that area and increasing the link with the bokeh girl in the background which I presume is an integral part of your work.
Forum: Photographic Technique 02-02-2020, 12:44 PM  
Photography's Triangle
Posted By GUB
Replies: 99
Views: 2,580
Why do you feel her head is too light? Have you already pulled it back in post processing and are aware detail is lost there?
Nice shots.
Forum: Photographic Technique 02-02-2020, 12:24 AM  
Photography's Triangle
Posted By GUB
Replies: 99
Views: 2,580
I don't do a lot of flash and then only fired manually for closeups so I have no idea how it pans out.
But if you are using flash and habitually using a higher ISO then it makes sense to try a -EV shot in TAv like Sevekan does. (post 32) Whether that works in tandem with the flash auto is beyond me.
I think his technique is an excellent way.
It doesn't work for me because I use old legacy glass which means TAv defaults to AV. Lenses need to be A series or later in A mode for TAv.
I don't use A mode because the LCD behaves differently in A compared to manual settings. (it goes dark in dark environments whereas in manual the LCD stays at an automatic brightness)
That is why I am in M mode looking at digital previews. But the simplicity of that combined with the simplicity of manual lenses suits me.
Forum: Photographic Technique 02-01-2020, 11:10 AM  
Photography's Triangle
Posted By GUB
Replies: 99
Views: 2,580
"Vehemently" is a bit of a strong word for it.I used the term "bickering" (as in children in a family environment) earlier in a lighthearted way.


Whether you like it or not the triangle changed at the advent of digital.
In film ISO was a measure of sensitivity
In digital it is a measure of gain.

One affects the image at the moment of image taking
One amplifies the errors of the sensor downstream from the image taking.

As for base ISO - the camera makers would tell you it is the native signal from the sensor that ISO adjustments amplify downstream. We know it aint that simple.
Forum: Photographic Technique 02-01-2020, 03:53 AM  
Photography's Triangle
Posted By GUB
Replies: 99
Views: 2,580
Modern ISO (and +EV in post) is so good I think it is more the art of trade offs than last resort nowadays
For instance in my 50 1.7s there is a distinct IQ boost to f2 so even in very lowlight conditions it makes sense to go f2 and put up with half a stop of extra noise.
But if I felt the need to go from 1/50 to 1/25 with the 50mm and my subject was pretty static I would take a leap of faith in image stabilization rather than further increase the noise.
But every situation is different and everyone is different.
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