[UncleVanya]

This is odd. Look at these 2 28-105 pics- one is at f/4.5 and the other at f/11 . More or less same view. Using AV mode. What is the stuff at top right and top left on the 4.5 and much less so on the 11?? I looked at other tests and most of the rest were f/8 and f/11, but the f/4.5 ones all had this smudgie stuff.





Here is an OK one we saw before.



I *think* lens is OK.

Are these shots SOOC jpg? Is the rented K-1 set to correct peripheral illumination? If not what raw processor are you using and is it setup with a lens profile for this camera/lens?

---------- Post added 06-06-23 at 01:51 PM ----------

Oh well, I can keep it at f/8 or smaller.

You can easily correct that level of vignetting in post but as I ask above is that correction disabled in the camera for jpgs?

---------- Post added 06-06-23 at 01:54 PM ----------

Yes, I knew I'd have to rent a FF to test this particular lens. I'm sure it would be fine on my K-3 III but it would not be 28-105 any more.

Not to be argumentative- it’s still 28-105 on both cameras. Set any 28 on the apsc and it will look the same. The thing is that 28mm is nearly a normal lens on apsc and is a moderately wide angle on the ff.

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Last edited by UncleVanya; 06-06-2023 at 10:55 AM.

[madison_wi_gal]

Are these shots SOOC jpg? Is the rented K-1 set to correct peripheral illumination? If not what raw processor are you using and is it setup with a lens profile for this camera/lens?

---------- Post added 06-06-23 at 01:51 PM ----------



You can easily correct that level of vignetting in post but as I ask above is that correction disabled in the camera for jpgs?

---------- Post added 06-06-23 at 01:54 PM ----------



Not to be argumentative- it’s still 28-105 on both cameras. Set any 28 on the apsc and it will look the same. The thing is that 28mm is nearly a normal lens on apsc and is a moderately wide angle on the ff.

1 - yes, RAW only, minimal processing in LRC (auto whatever)
2 - Not shooting JPGs but I think I turned correction off anyway
3 - OK, I am saying it wrong.

[Lowell Goudge]

Yes, I knew I'd have to rent a FF to test this particular lens. I'm sure it would be fine on my K-3 III but it would not be 28-105 any more.

a 28-105 is always a 28-105 regardless of how it is cropped either in post processing or by the camera sensor. but lets not open that discussion.

you should do the vignetting and exposure test anyway on the K3 as well, since with digital vignetting is not only caused by the lens and light distribution but also by the sensor/microlens design and the angle the light hits the sensor .

my K50/1.4 shows a 1/3 stop of vignetting even on a crop sensor DSLR. you need to measure it to see it, and it does not really impact the image quality BUT IT IS THERE.

[madison_wi_gal]

OK, according to Pentax-Ricoh I have until June 10th to return, even though I got it May 15th. Grr. Will test if I can make the time, but if this is a known thing and it looks gorgeous at smaller f stops maybe I don't care.

[Lowell Goudge]

, but if this is a known thing and it looks gorgeous at smaller f stops maybe I don't care.

That’s the best attitude

[UncleVanya]

My main point is that you can easily fix the vignetting at wide open if it bothers you.

And please don’t take what I said about the focal lengths wrong. I’ve had people who thought an apsc 28mm would act different than a ff 28mm on the same apsc camera. They both give the same rough angle of view on the same apsc camera. Done adding the ff lens is different and that’s what causes it. I apologize if that seemed too picky.

[madison_wi_gal]

My main point is that you can easily fix the vignetting at wide open if it bothers you.

And please don’t take what I said about the focal lengths wrong. I’ve had people who thought an apsc 28mm would act different than a ff 28mm on the same apsc camera. They both give the same rough angle of view on the same apsc camera. Done adding the ff lens is different and that’s what causes it. I apologize if that seemed too picky.

No worries, I accept my confusion about focal lengths and the general problem of how to explain it to a novice. I just go by the page here that says that a FF lens (Señor 43, for example) on my borrowed K-1 II will have a FOV of 53 ° / 45 ° and on my K-3 III, my K-r, My K-30 and my 2 K-01s it will have a FOV of 37 ° / 31 °. Those numbers are different, therefore Señor 43 gives different results on a FF vs an APS-C camera. What the correct terminology to use when explaining it is a problem for me, so I default to using incorrect terminology.

It will still be a 43 mm lens and it even has a 43 printed right on it to remind me what it is.

I also know that putting my beloved 18-135 on my borrowed K-1 II might be problematic, but putting my 28-105 on my K-3 III is okie dokey.

So because of that, any future LBA ought be be leaning towards certified FF lenses (or at least the longer focal lengths) on the off chance that someday I'll have my Viridian.

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Last edited by madison_wi_gal; 06-06-2023 at 05:25 PM.

[UncleVanya]

No worries, I accept my confusion about focal lengths and the general problem of how to explain it to a novice. I just go by the page here that says that a FF lens (Señor 43, for example) on my borrowed K-1 II will have a FOV of 53 ° / 45 ° and on my K-3 III, my K-r, My K-30 and my 2 K-01s it will have a FOV of 37 ° / 31 °. Those numbers are different, therefore Señor 43 gives different results on a FF vs an APS-C camera. What the correct terminology to use when explaining it is a problem for me, so I default to using incorrect terminology.

It will still be a 43 mm lens and it even has a 43 printed right on it to remind me what it is.

I also know that putting my beloved 18-135 on my borrowed K-1 II might be problematic, but putting my 28-105 on my K-3 III is okie dokey.

So because of that, any future LBA ought be be leaning towards certified FF lenses (or at least the longer focal lengths) on the off chance that someday I'll have my Viridian.

The da lenses that aren't zooms starting at 35mm tend to cover full frame. There are articles about this and forum posts. Don't be afraid of da lenses just plan to get those that are more ff friendly.

The key message is that a legs may cover more than it's sold for. But the quality of the edges could be degraded.

Angle of view isn't bad. Honestly what you need to say isn't clear to me either.

[madison_wi_gal]

The da lenses that aren't zooms starting at 35mm tend to cover full frame

OK, might be confused here. I need to go back and look, but I thought you said that lenses less than 35 (like my 15 and 21) are full framey on APS-C. If you said bigger than my bad,

[UncleVanya]

OK, might be confused here. I need to go back and look, but I thought you said that lenses less than 35 (like my 15 and 21) are full framey on APS-C. If you said bigger than my bad,

My mistake if I did. Of the da limited series the 35 macro is borderline depending on aperture etc. the regular plastic fantastic da 35 is quite ff capable. The da* 55 is ff capable also. The da 15 and 21 will do a square crop larger than apsc in height.

Some zooms for apsc work partially on ff. Some like the da* 60-250 are quite good and can be modified to be better. Some like the 18-135 / 50-135 can’t do much outside apsc if any.