[nonpigliounoshoot]

Hello Pentaxians, i just got a 28 k 3.5 and I saw that on k1 at full aperture the 35 k 3.5 vignette discreetly, I didn't think I had read anything about it before. Closing it obviously improves until it disappears from f8. In apsc mode no problem, from which I deduce that even on k70 there should be no problems. Is it just a problem with my specimen or does it happen to others too?

[jopenmx]

Which hood are you actually using in the combo K-1+K 28f/3,5 ? I have the original square hood of Pentax SH-52, and never had any problem of vignetting. Also have a Nikon round hood HN-2 of 52 mm. , that produce also good results.

[pschlute]

To be honest all lenses vignette to some degree. The "K" 28mm 3.5 is no exception.

[nonpigliounoshoot]

I didn't have a hood with me, I'll try to put one in circular rubber tomorrow.

Many thanks

[AstroDave]

I didn't have a hood with me, I'll try to put one in circular rubber tomorrow.

Many thanks

Don't bother (unless you've got glare or some other reason) - any hood will only (but not neccesarily) make things worse! i.e. if the hood constricts the field of view, it might add to the vignetting. If it doesn't, you are still at the mercy of the lens itself.

[pinholecam]

You might want to share some shots as examples of the vignette.

I don't see anything too distinct on my lens and all lenses vignette a bit wide open.
So its a bit subjective on what the user expects. (unless its very obvious physical vignetting like from a hood or filter ring)


The lens is so-so for wide open shooting anyway (imho) and it really shines for stopped down shooting.

[clackers]

Wide angles vignette on full frame at the wider apertures, nonpigliounoshoot, especially little ones like the K28 f3.5, that's how they are. The DFA 28-105 is the same, so is a Zeiss 25mm or whatever.

Compensate in post processing as you see fit.

[nonpigliounoshoot]

You might want to share some shots as examples of the vignette.

I don't see anything too distinct on my lens and all lenses vignette a bit wide open.
So its a bit subjective on what the user expects. (unless its very obvious physical vignetting like from a hood or filter ring)


The lens is so-so for wide open shooting anyway (imho) and it really shines for stopped down shooting.

Thanks again to all. Meanwhile on apsc (k70) I confirm no vignetting starting from full aperture. On K1, on the other hand, I confirm with the photos some tests on 24k, 28K, 28A, 55k at full aperture (I forgot the 35 to 2.8 patience). The best in a sense is certainly the 55k where vignetting is practically almost absent since 1.8 (even if a thread is overexposed and therefore helps). Obviously for all diaphragm also on k1 it attenuates from 5.6 it is very light and at f8 it disappears. Just to close my circle. This is the photo with 28 3.5 at full aperture on k1

[clackers]

Hello Pentaxians, i just got a 28 k 3.5 and I saw that on k1 at full aperture the 35 k 3.5 vignette discreetly, I didn't think I had read anything about it before. Closing it obviously improves until it disappears from f8. In apsc mode no problem, from which I deduce that even on k70 there should be no problems. Is it just a problem with my specimen or does it happen to others too?

Since you own the FA31 Limited, I'm surprised you haven't noticed its vignetting.

Here it is, courtesy of Guest Review: Pentax SMC FA 31mm f1.8 Limited - phillipreeve.net

Would this fail the Pentax Forums DA compatibility test?

[nonpigliounoshoot]

Since you own the FA31 Limited, I'm surprised you haven't noticed its vignetting.

Here it is, courtesy of Guest Review: Pentax SMC FA 31mm f1.8 Limited - phillipreeve.net

Would this fail the Pentax Forums DA compatibility test?

Beh in realtà il problema me ero posto anche per il 31 quando avevo visto questi test. Ho comprato la lente prima di k1, usando su apsc e ovviamente non vignettava. Quando ho preso k1 avevo un po di timore per quel test, in realtà però nella vita reale a me non compare quella vignettatura così accentuata. Ho fatto recentemente una sessione di ritratto a tutta apertura e non ho avuto problemi così evidenti e di questo sono molto contento, forse il mio esemplare è migliore di quello del test, or maybe some problem due to adapter, o forse fare foto ad un foglio bianco serve a mettere paura. Finally, consider that normally I don't need to use 1.8, but I use 3.5 or a little more can be, and it is very different.

[clackers]

Beh in realtà il problema me ero posto anche per il 31 quando avevo visto questi test. Ho comprato la lente prima di k1, usando su apsc e ovviamente non vignettava. Quando ho preso k1 avevo un po di timore per quel test, in realtà però nella vita reale a me non compare quella vignettatura così accentuata. Ho fatto recentemente una sessione di ritratto a tutta apertura e non ho avuto problemi così evidenti e di questo sono molto contento, forse il mio esemplare è migliore di quello del test, or maybe some problem due to adapter, o forse fare foto ad un foglio bianco serve a mettere paura. Finally, consider that normally I don't need to use 1.8, but I use 3.5 or a little more can be, and it is very different.

And also bear in mind that the JPGs at least are automatically corrected for vignetting by the camera, it brightens the corners.

But the vignetting is at least 2eV in the corners, according to a test done in this very forum!

And most wide angle lenses from all camera brands suffer from this unless the lens itself is big and heavy, containing a lot of glass.

[nonpigliounoshoot]

And also bear in mind that the JPGs at least are automatically corrected for vignetting by the camera, it brightens the corners.

But the vignetting is at least 2eV in the corners, according to a test done in this very forum!

And most wide angle lenses from all camera brands suffer from this unless the lens itself is big and heavy, containing a lot of glass.

I know the function, which is activated on the camera. I attach two photos taken now at 1.8, without correction of the camera. As you can see the vignetting is lower equally, and the one on the right is caused by the shadow of my snap point (the light comes from the left from an internal window). For shots in other situations I would say that even without corrections it is not noticeable. I don't want to argue that it doesn't produce any, I'd be silly, but just that I thought it was less relevant and that for 31 it's not strange that I didn't notice when it happens in much rarer situations of my use.
(jepg only resized). In any case in the end the purpose of my question was to understand if it was a problem with my lens 28 3.5 k, probably a little more or less depending on many reasons, but it is a common thing. Thanks.