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Forum: Pentax SLR Lens Discussion 01-20-2023, 09:55 AM

Pentax FA* 200mm F4 Macro vs adapted FA 645 120mm F4 MACRO
Posted By loji

Replies: 17
Views: 1,111

For those interested ...

I got the Leica R-180mm 3.4 APO ... optimized for infinity, corrected form visibile to infared. A steal for a few $$ converted with Leitax.

Here's a quick handheld comparison on a K5iis, all at 5.6 .. at maximum crop

top Left = Pentax M 75-150mm F4
top Right = Leica R-180 APO 3.4
bottom Left = Pentax DFA WR 100 Macro 2.8
bottomw Right = Pentax 645 FA 120 Macro

All shot at 5.6, handheld through a window ... took two pictures and grabbed the sharper of the two. Jpegs straight out of the camera with no edits. This is just a screenshot from my laptop screen, not an export, and no LR... just image preview.

the Leica is VERY sharp at this extreme level of crop ... probably sharper than the K5 sensor can handle.
It also has the least amount of contrast. (no coating. this is a 1977 version)

To show how extreme this crop is .... I've attached a view from the window I was at.. . the Left side is taken with a GRIII, which is what the 'feel' of sitting at the window is like . . . the right side is the uncropped WR100mm view

So pretty extreme that a jpg crop this deep shows any details at all ... the APO Leica is astounding (if crappy contrast) but that can be easily fixed in post.

Forum: Pentax SLR Lens Discussion 01-04-2023, 08:33 AM

Pentax FA* 200mm F4 Macro vs adapted FA 645 120mm F4 MACRO
Posted By loji

Replies: 17
Views: 1,111

Thanks for this tid-bit ..... after research I ended up buying a Leitz/Leica Telty 180mm 3.4 APO .. optimized for infinity, and extremely sharp!

Got it for a great price, it's a 1977 version. I'm awaiting the leitax adapter for it, but will update when it arrives and I can test out the lens

it came with a bundled Pentax M-70-150 f4 ... so will be interesting to compare them. the zoom has much more CA but was basically free.

Forum: Pentax SLR Lens Discussion 12-15-2022, 03:07 PM

Pentax FA* 200mm F4 Macro vs adapted FA 645 120mm F4 MACRO
Posted By loji

Replies: 17
Views: 1,111

Thank you ... In all my examples above, I assume I'm standing in the same spot. ie: fixed perspective. and shooting say a distant island (another fixed point)

so I AM getting the same compression as a 480mm lens, with both the adapted m43 set-up ... or with the 120 on the Z and cropping ...

but the EV light gathering/metering , and depth of field would be different in each scenario .. ?

I had researched the F*300/f4.5 ... but it's so flashy (looks like the cannon glass) and screams " Look at me, I'm a big photographer" .. trying to stay as low-profile as possible

walking around the the Z is not exactly subtle either ... but it seems I'm not gaining much using the K5 and F*300 vs the 120/Z and cropping to 300mm . . . at least the Z is black

Forum: Pentax SLR Lens Discussion 12-15-2022, 02:23 PM

Pentax FA* 200mm F4 Macro vs adapted FA 645 120mm F4 MACRO
Posted By loji

Replies: 17
Views: 1,111

Nothing wrong, it's one of my favorite lenses.. I've always lived in a tight city, now I live on the open coast ... so I never had any need for tele-photo, but with this much nature/wildlife/boats around . . . it might be fun.

Which leads me to my next question ... adapting and light transmission, vs cropping . . . and sub question : adapting/cropping and image compression vs field of view and depth-of-field. I *think* I have a good grasp, but . . . .

currently to hit telephoto, I can do the any of the following ...

645 120m f4 -> 645:K adapter -> K:m43 adapter > Olympus m43 (2:1 crop sensor) ... and the camera has an internal 2x digital crop... ie: it's cropping digitally before the exposure meter

SO: I take that as I have 120mm/f4, x2 (2:1 crop sensor) = 240mm f4, plus the digital crop in camera = 480mm f8? (f8 EV because 1/2 of the light picked up is thrown away in the crop?)

BUT: that 240mm f4, still has the image-compression characteristics of a 120mm lens (ie: the background doesn't compress twice as much, just the field-of-view is tighter)

same after the digital crop to 480mm ... my field-of-view is narrower, but the 'look' or image-compression isn't magnified .. it's still the same 120mm compression 'look'. . . is that correct?

Additionally, the depth-of-field is the same as the f4 setting wide-open on the lens, so in this case I would be shooting an equivalent 480mm field of view, with a f8 EV metering, a 120mm image compression, and a f4 depth of field? . . . or is that totally wrong?

A different example ...

the DFA 100 f2.8 -> 1.4 TC (-1 stop EV) -> K5 ... would look and act like a 140mm f4 in terms of image-compression and EV light gathering ... and on the K5 APS crop sensor (1.5 : 1) .. would have an equivalent field of view as a 210mm, but the compression characteristics of a 140mm lens.

Ok . . . so if I understand it correctly ... the 645Z has a 51.4MP .. the K5 and Olympus are each 16MP ..

So if I mount the 645 120mm f4 native on the Z ... I'm metering the whole scene, so EV is a f4, lens compression, and depth of field all stay the same f4 ... but to match the Olympus with it's internal 2:1 crop, I could crop the Z picture in post ..

120mm f4 EV = 51.4MP
240mm f4 EV = 25.7MP
480mm f4 EV= 12.85MP

Since the crop on the Z is happening post EV meter, I'm not loosing anything in light gathering ability ... I still have the image compression, and depth of field as the original 120mm f4 (same as the adapted Olympus m43 option) ... and in both cases the field of view is narrowed to a 480mm equivalent.

and across all these variations, none of it changes the minimum focus distance?

** head scratch **

Forum: Pentax SLR Lens Discussion 12-15-2022, 08:48 AM

Pentax FA* 200mm F4 Macro vs adapted FA 645 120mm F4 MACRO
Posted By loji

Replies: 17
Views: 1,111

I only shoot primes, I use a GR3 for my wide-angle, (18mm)

on my K5 I have the DA35 Macro, FA43, A50, FA77, DFA-100 Macro

and on 645Z .. I have A35, DFA-55, FA75, FA-120 Macro

A nice little collection there .... I was looking at a tele to round it out, and I prefer the look and flexibility of Macro-tele's (opposed to something big and flashy like the F*300)

the price for the FA* 200 Macro is HUGE . . . and I already own the 645 120 Macro and 645 to K adapter . .

on my K5, the 645 120mm, would be about a 200mm field of view on the crop sensor....

So what am I missing ?

the 645 FA-120 Macro is smaller and ligher than the FA*200 ... cheaper, can be used on two systems and I already own it . . .

it's a long shot, but does anyone have experience with both lenses? . . .

Forum: Sold Items 12-14-2022, 05:31 PM

For Sale - Sold: Pentax 645Z with Pentax 645 with 4 Pentax 645 Autofocus Lenses
Posted By loji

Replies: 5
Views: 920

GREAT price!!

Forum: Post Your Photos! 05-25-2022, 08:48 PM

21mm Photo Contest Extra Ordinary - Poetry Petals
Posted By loji

Replies: 5
Views: 281

Thanks Angky, appreciate the kind words

Forum: Post Your Photos! 05-23-2022, 08:47 PM

21mm Photo Contest Extra Ordinary - Poetry Petals
Posted By loji

Replies: 5
Views: 281

Thanks for the feedback ...

I came up with the idea a few years ago, I personalize them and sell them in floating frame boxes on my etsy store : Mothers Day Personalized Flower : Rose Petal Suspended | Etsy

Popular item for the ladies ;)

Forum: Post Your Photos! 05-23-2022, 03:18 PM

21mm Photo Contest Extra Ordinary - Poetry Petals
Posted By loji

Replies: 5
Views: 281

Hand typed poetry on a rose petal, made through a vintage WWII typewriter (swiss made)

Forum: Post Your Photos! 02-06-2022, 12:27 PM

2021 Pentax Lens Tournament SMC Pentax DA10-17mm F4 Fisheye Zoom Lens
Posted By loji

Replies: 5
Views: 314

I actually have one of these for sale (I couldnt' post on classifieds, but PM me for the ebay link) ... this lens has created some of my FAVORITE pictures to date . .

One aspect that doesn't get enough love is it ia Macro Focusing with a 180 field of view ... so you can get right up into something, and still the environment surrounding it to give context.

will give a great deal to a fellow Pentaxian here :)

I'm only selling to help fund a GRiii purchase .. if I carry a big DSLR with me, it's the Z .. so this excellent lens needs a new home

---------- Post added 02-06-22 at 01:33 PM ----------

Taken on a moving subway, through glass over the Manhattan Bridge .. .

Macro focusing (only 3-4" away from the statue nose)

at 17mm the fisheye effect goes away, the SMC coating gives excellent color