Hi Vic

I am actively buying and selling a significant quantity of camera equipment on ebay, specifially Pentax gear. K1's with approx 4,000 clicks on the shutter are selling for about £900, if that's any help.

Regards
David

pm sent

Hi John

I read your review before buying the lens and it was one of the reasons I bought it. However, since using it I have not been overly impressed. It is sharper at the edges of the frame than my cheap Cosina, but not in the parts of the image that really count. It also exhibits a fair amount of red and green CA, more so at the edges, but across the whole frame to some extent. I did another test today, comparing with my Pentax-M 28mm F/3.5, both lenses at F11 and the old 3.5 beat it across the whole frame. I know the M3.5 is a prime lens, but it's nearly 50 years old! My copy of the 28-105 is comfortably out-resolved by the K1.

Unfortunately, I can't return the lens, so it will be sold.

Regards
David

Hi All

I have a rather specialist item for sale on ebay at the moment, it's the revered SMC Pentax 28mm F/3.5 Shift lens. It's up at £545, but I would take an offer close to £500 if anyone here is interested in it, or knows someone that would like it. This particular one is in near-mint condition, apart from a very small dent to the filter ring. The ebay listing is:

link

Please message me if interested and I will be happy to sell direct to a forum member.

Best regards
David

That's just a great image! Very well spotted and taken.

Regards
David

Hi Defragged, I'm not surprised you can't see the difference in these tiny images on the Forum, but believe me it's blindingly obvious when you see them full size! The Pentax (my copy at least) is truly awful against these two very cheap zooms. If it can't beat a Tamron 28-300 at 28mm, there's something really wrong, but it's true! It gets nowhere close. It shocked me, particularly as this lens was designed for the K1.

I would like to hear from other DFA 28-105 owners to see what they think of their copy, as mine might be a 'wrong-un', but I somehow doubt this. My gut feeling is that it's just not a great lens.

Regards
David

Hi All

A quick update on my search for lenses to use with the K1. Whilst I'm looking for some nice, cheap primes that can do the K1's sensor justice, I also need some travel / walk-around zooms. I had already purchased the DFA 28-105, with a view to testing this against some other lenses to see if it's worth keeping. First impressions of this lens were slightly mixed, colours and contrast very good, but sharpness? I wasn't convinced. So, I also have two very cheap full frame zooms, a Cosina 19-35 f3.5-4.5 and a Tamron superzoom 28-300 f3.5-6.3. The cost of the three lenses:

Cosina 19-35 = £30
Tamron 28-300 = £53
Pentax 28-105 = £340

As my main interest is landscapes and wide angle photography, I tested all three lenses today side by side at 28mm. Tests were on a tripod, Aperture at f11, ISO 100, 2 second self timer to avoid any shake, focused manually on a road sign in the centre of the image using live view focus peaking to ensure all were correctly focused. I have purposefully under-exposed the images to avoid any blown highlights. The results were quite astounding and as follows:

Centre Sharpness: Best = Cosina (by a large margin), second best = Tamron, worst (by a long way) = Pentax

Edge Sharpness: Best = Pentax (small margin), second best = Tamron, worst = Cosina, but margins here are small and not a concern to me

Colours / contrast: Best = Tamron, second best = Pentax, third = Cosina, but all were good and the Cosina images can be brought easily up to the same level in post processing

Chromatic Aberrations: There was very little between the three, but what shocked me were the CA's the Pentax lens exhibits at the edges, even on subjects that are not particularly contrasty. For edge CA's, the Pentax lens is by far the worst of the three.

You might not be surprised to hear that I'll be selling the DFA 28-105 after not being very impressed initially and then having suspicions confirmed by these tests. Clearly at the wide end, the 28-105 is not very good, or at least my copy is not very good! Would be interested to hear what others think of this lens. BTW, all three lenses are in pretty much mint condition.

Here are the 3 images, these are from RAW files that have not been adjusted in any way, they are straight from the camera with no sharpening, no contrast changes, just a tweak to exposure to make them all viewable.

Cosina 19-35:



Tamron 28-300:



Pentax 28-105:



My advice following these tests, if you want a basic walk-around kit for a K1, get a Cosina 19-35 and a Tamron 28-300!

Any thoughts / observations welcome, you might find it difficult to see the difference in the small image sizes the forum allows, but I have zoomed them to 200% in photoshop to inspect them side by side.

Regards
David

Thanks for all the lens suggestions, tbh they are a bit on the expensive side for me at present. I do have some nice lenses on the way which I will try, including a SMC Takumar 28mm f/3.5, which I understand to be the same optical formula as the renowned K 28 f/3.5, so I have high hopes for this one. Also have a K 35 f/3.5 coming soon, although it has fungus and will need a clean, also a K series 24mm f/2.8.

I'll try all these out, along with a cheap Cosina 19-35mm f/3.5-4.5 AF zoom, which will work fine on FF, but i don't hold out hopes for this being much good. We'll see when it arrives.

Regards
David

Thanks for all the input so far, it's been helpful

As an aside, now I have the K1, I'm on the lookout for a wide angle lens that can do justice to the K1's sensor. When I mean wide angle, I mean a prime lens and it will be a vintage one as I can't afford a DFA lens. So, I'm looking for suggestions, based on experience, in the 20 to 28mm focal range, lenses that can be sharp across the frame and will work well on a K1 without vignetting. I already have a K series 35mm f/3.5, a M series 28mm f3.5 and I have a K series 24mm f/2.8 on the way. I also have a Sigma 24mm Super-wide, but given lockdown I haven't yet had the chance to really test these lenses.

If anyone can point me in the direction of a wide-angle vintage lens that will really do the K1 justice, please let me know. I don't care if it is AF or MF.

Thanks in advance!

Regards
David

Thank you very much! I've been lurking and posting on the gallery, just not on the forum very often.

Regards
David