[normhead]

The measured lw/ph of a k-5 is ~2100. The measured lw/ph of a k-3 is ~2700 I am kind of interested where this data comes from

Look under resolution. K-5
Pentax K-5 Review - Image Quality

Very high resolution, ~1,900 lines of strong detail from JPEGs, about 2,100 lines from converted RAW files.

K-3
Pentax K-3 Review - Exposure

Very high resolution, ~2,700 lines of strong detail from JPEGs, about the same from converted RAW files.

Instead of using your real world estimation lets use testing under lab conditions from you favorite site.

Ya? Let's not, I'm interested in how things do in the real world... not in a lab. Shooting 2d test charts hides a lot of flaws.

Seriously, I've done enough and demonstrated exactly what I'm talking about. People can choose to go with what makes sense to them.

Nice images by the way, but they look heavily processed. Is Nikon really that good or did you enhance in post processing? As mentioned in another thread,, in which I provided images, post processing can make some of the images from my worst lens acceptable.

Listed in another, TC's only add detail in some circumstances. There will be some situations where the TC makes no difference , as you move back, there is a range where the TC makes the difference it's rated for, and if you move back even further, either with or without the TC provides no relevant detail in the image. It depends on the amount of detail in the subject, and lens focal length required by the subject, just where that range will fall.

The reason for the TC being the same some times, is the subject doesn't have any fine detail. But, if you capture the subject detail of say a bar code on a box, then back up until you can't read the print anymore with a given lenses, and then put the TC on it. You'll get another few feet of legible print in your images. I've done it and posted here on the forum. The results were pretty straight forward.

The thing with the HD DA 1.4 TC is, it won't make it worse, but it might make it better. I make no promises for TCs from other manufacturers. Apparently some of them are not as good as cropping the smaller pre-TC image.

The goal here is to understand the advantage provide by your gear. Not negative opinions on why everything doesn't work. The trick is to discover how they work.

The fact that you label my test inaccurate doesn't make it so, and it definitely doesn't make it less valuable than what you've posted. Especially given your inaccurate conclusions. The crop factor is 1.5. everyone knows it. Your extraordinary claims require extraordinary proof.

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Last edited by normhead; 02-11-2022 at 09:47 AM.

[luftfluss]

There is so much good information here, thanks to everyone that's responded to this. I've looked and searched and looked some more. I almost came to the conclusion to buy a Nikon D810 and the 200-500. They both get rave reviews and can be had used for under $2000 for the pair. I could put my FA*80-200 on the K5 and use the Nikon for the longer shot. Maybe I should consider the D7500 Crop sensor too. I have a couple items watched on evil bay with a few days to go. HOWEVER, just as I was typing this it occurred to me, what if for now, I got the Pentax af 1.7 adapter? That gets me to 510mm, granted its a little slower and then I could decide if 500mm was long enough. If not, maybe I get a 645 A*600mm and the adapter to PK mount. I see them around the $2000 price as well. Still not sure the 150-450 gains me anything over the current 420 I have with the 1.4 TC. Well, I guess it does get me to 630mm but at about F7 with the TC. So I ramble on about options, and really there are options. A D810 was what I was thinking about back when I decided to stay with Pentax.


So, after all that, let me ask this question, have any of you used the 1.7 AF adapter on the DA* 300mm F4? were the results reasonable?

Thanks for putting up with my indecision! or tightwaddness


Tim

I've used the AFA 1.7x adapter on my Tamron 300/2.8, which has similar sharpness to the DA 300/4, and the results were pretty good.






Very heavy crop, either 100% or close to it.



I don't know how the combo would do shooting at far distance, though. Most of my shooting is in fairly wooded areas, so I seldom have the opportunity.

[normhead]

I've used the AFA 1.7x adapter on my Tamron 300/2.8, which has similar sharpness to the DA 300/4, and the results were pretty good.

Very heavy crop, either 100% or close to it.

I don't know how the combo would do shooting at far distance, though. Most of my shooting is in fairly wooded areas, so I seldom have the opportunity.

The AF adapter loves 2.8 glass. I'd venture to say it was designed for 2.8.

[luftfluss]

The AF adapter loves 2.8 glass. I'd venture to say it was designed for 2.8.

Yeah, in the Lens Database there is this:

The converter is designed for lenses with a maximum aperture of F2.8 or larger, and a focal length from 16mm to 400mm.

Given that the AFA's production run was prior to digital at 1987-1997, what kind of AF sensitivity did the Pentax film cameras have? f/5.6?

[gatorguy]

My wife and I went eagle watching a couple weeks ago. The eagles were mostly on the opposite side of the Mississippi river. They were mostly smallish birds with my 300. I have the DA 1.4 converter, that I forgot (didn't check to make sure it was on the lens when we left home). So my wife says "you need a longer lens"! Thats an invitation to get something looong.

I would like 600mm but truly I don't want to spend $4000 or $5000 on one.

The options I see are:
DFA 150-450 but that doesn't get me to 600 unless I use the converter. Used it can be had for around $15-1600.

A*600 f5.6 under $2000 but manual focus,

F*600 f4.0 I'd be happy with a well used one as long as the glass was good.
FA*600 f4.0 again well used is fine but the F and FA are well above what I want to or can spend.
Then there's the FA* 250-600, there's even one for sale here on the forum. Again well over what I want to spend.

I guess the K 135-600 and K500 would be options too but not sure it's what I want.


If you were spending your money and I'm retired so somewhat limited income, what would you do? Ideas? Have I over looked anything?


Currently my longest lens in the DA*300 + DA1.4 converter at 420mm.


Thanks

Tim

These are from a sub-$400 lens, the Sigma 170-500 DG APO. Taken both with and without the Pentax 1.4TC. Oh and it's EAGLES, taken approx 600-700 feet away.

First one is at 500mm and a 100% crop. Not bad for a distance shot IMO
It's here tho that Topaz is your friend. 2nd is the same 100% crop after a bit of cleaning
And then finally at 170mm to give you an idea of zoom range.

[gatorguy]

BTW, that Sigma 170-500 performs much better the closer you are to your subject. As Norm pointed out a few posts back, even with a long lens it's very advantageous to get as close to the subject as possible.
This is the neighbors fat cat from about 10 yards, including a 100% crop of that photo. Clean!

[wadge22]

-Sigma 135-400. There might be a similar Tamron or Tokina as well, I can't find it now so maybe not.

This is the one I was thinking of: Tokina AT-X 80-400mm f4.5-5.6

[gatorguy]

This is the one I was thinking of: Tokina AT-X 80-400mm f4.5-5.6

You should add this one to your list too:
Sigma 170-500mm F5-6.3 APO DG Lens Reviews - Sigma Lenses - Pentax Lens Review Database

[aslyfox]

did you folks see this one for sale ?

Used SMC Pentax FA 250-600mm f5.6 ED - 1 YEAR GTEE
£3,999.00

SMC Pentax FA 250-600mm f5.6 ED - PentaxForums.com

https://www.pentaxforums.com/lensreviews/SMC-Pentax-FA-Star-250-600mm-F5.6-Power-Zoom-Lens.html

[gatorguy]

did you folks see this one for sale ?



SMC Pentax FA 250-600mm f5.6 ED - PentaxForums.com

SMC Pentax-FA* 250-600mm F5.6 ED [IF] Reviews - FA Zoom Lenses - Pentax Lens Reviews & Lens Database

OKAY! Digging down deep into the couch cushions tonight.

[aslyfox]

OKAY! Digging down deep into the couch cushions tonight.

ok

that's my " daily good deed " accomplished

[fuzzyphotos]

ok

that's my " daily good deed " accomplished

And thank you for that Allen. I dug into the couch, car seats and everywhere else and came up short. This would be a dream lens for sure. Maybe I should start a go fund me page for the new lens.

Thanks for posting it.

[aslyfox]

And thank you for that Allen. I dug into the couch, car seats and everywhere else and came up short. This would be a dream lens for sure. Maybe I should start a go fund me page for the new lens.

Thanks for posting it.

I can't take the credit

it belongs to @Ducatigaz

https://www.pentaxforums.com/forums/94-pentax-price-watch/438239-smc-pentax-...ml#post5516897

[gofour3]

The fact that I can shoot a roaming fox near 8 pm on a cloudy evening, and get good fur detail with the lens wide open, has me enthusiastic about the K 500/4.5..

I've had good results with the K500/4.5 as well, but I have to really watch for vibrations shooting with slower ISO film/shutter speeds. It's bigger brother the K1000/8 is twice as bad for vibrations. You really need a good tripod/head & camera end support and I also use MLU on my film cameras/with cable release to get good results. Mostly stationary subjects though......:

Phil.

[Ian Stuart Forsyth]

but they look heavily processed. Is Nikon really that good or did you enhance in post processing?

If this is heavily processed as seen in rawdigger


ARC

in which I provided images, post processing can make some of the images from my worst lens acceptable.

With tell tail artifacts



Fine detail is harder to create from nothing

Listed in another, TC's only add detail in some circumstances.

Sure it can but it is no substitute to shooting with a lens with a larger FL and many times it is bested by a zoom that you are trying to to equal in FL

The thing with the HD DA 1.4 TC is, it won't make it worse, but it might make it better.

Most of the time will not make it into a FL that is equal to a FL you are trying to convert it into.

The goal here is to understand the advantage provide by your gear. Not negative opinions on why everything doesn't work. The trick is to discover how they work.

And to understand that you cannot hope to change a 300mm lens into a lens that will capture 1.4x1.5=2.1 converted 630mm. any native lens shot at 600mm will be well ahead and would have to be a rather poor lens not to be equal to it. This is very basic stuff man

The fact that you label my test inaccurate doesn't make it so,

Just saying that a FF 36mp camera with a 600mm lens used in a 1.2 crop mode will give you a FOV of 700mm lens with very little loss to IQ and 25mp of sensor resolution

And oh it was you that said that my work was inaccurate . lets see a 600mm lens shot using a FF camera with a 1,2 crop gives 50cm FOV horizontal


To 57mm FOV horizontal

and as for what a FF 36mp shot in 1,2 crop mode will produce you can look it up ( hint is 25mp)