[biz-engineer]

Once again there will not be a Full Frame teleconverter because one is Not Needed, they all work on any Pentax K mount model.

You are right, the Pentax APSC TC works on full frame, produces dark corners with 2 to 3 stops of light and sharpness fall off. Y
ou also lose 1 stop of light, so you have to either increase ISO (more noise) or decrease shutter speed (blurred photos), and all AF points are in the center of the frame.

If you use crop mode instead of using a TC on full frame, you have several advantages:
1) no vignette
2) no loss of light, makes auto-focus more responsive.
3) faster shutter speed (freezes motion, reduces shutter shock/mirror blur) or lower ISO (less noise)
4) faster burst rate on the K1 ( 7 FPS in crop mode instead of 4 FPS full frame)
5) in crop mode or crop camera , AF points almost cover the entire frame, = better for auto-focus tracking. On full frame + TC , AF points coverage is only in the center of the frame.

I should have also added to my earlier post, that I have used the DA 1.4x TC quite a bit with the K-1 and the DFA 150-450 for birding, and for me the combination worked well.

Yes you can. I was told "you can print 5 meters wide images from a smartphone", and yes you can. Is it any good?

---

Last edited by biz-engineer; 06-05-2022 at 11:29 PM.

[Lowell Goudge]

While I agree with many of your points, in theory, there are some practical limitations

You are right, the Pentax APSC TC works on full frame, produces dark corners with 2 to 3 stops of light and sharpness fall off. Y
ou also lose 1 stop of light, so you have to either increase ISO (more noise) or decrease shutter speed (blurred photos), and all AF points are in the center of the frame.

true to an extent but… I have shot up to ISO25000 at night with the K1MKii you can get some good images even under those trying conditions.

If you use crop mode instead of using a TC on full frame, you have several advantages:
1) no vignette

I think the op plans to crop plus use the TC or the image is sufficiently large that it exceeds the crop area, and opts for more total pixels

2) no loss of light, makes auto-focus more responsive.

true

3) faster shutter speed (freezes motion, reduces shutter shock/mirror blur) or lower ISO (less noise)

it is all a trade off, but note that increased magnification, regardless of how achieved means that all the motions can contribute to image blurr not just magnifications before the capture

4) faster burst rate on the K1 ( 7 FPS in crop mode instead of 4 FPS full frame)

true

5) in crop mode or crop camera , AF points almost cover the entire frame, = better for auto-focus tracking. On full frame + TC , AF points coverage is only in the center of the frame.

Shooting with multi point AF while birding is not always what you want. Most times you are looking to shoot only spot focus, because multi point picks up too much foreground, background or other things in the frame

Yes you can. I was told "you can print 5 meters wide images from a smartphone", and yes you can. Is it any good?

There is no right or wrong answer, but the issue is if you have only a K1 you need to remember regardless the crop mode is only 16 mp (I.e. like a K5) and when birding many times your image is probably only 1 MP because you are shooting from a long way away. It does not matter what mode you shoot, you are usually always cropping, BUT you may not want to shoot crop mode because of the times where you can fill more of the frame so you go for maximum pixels.

The other thing to point out is if I wanted to take your example to extremes, I could argue that we should be shooting with a 50mmF1.4, after all, you just need to crop more. But it does not work that way.

For birding especially, you never seem to have enough length, and there is some benefit in increasing the pixel count of an image by 2,

We are talking about the difference between a record shot vs nothing, or being able to identify what you see, vs not. This is not a discussion about making the absolute best sharpest image for publication, it is about getting an image at all.

I see many people insist on staying at ISO 100 and moan about noise, if they push their iso, but then complain that all their shots are blurry or they can’t take a shot because they would have to push the iso up, I would rather have a sharp shot with a little noise than no shot but that’s just me. Everyone can make their own choice

[biz-engineer]

I think the op plans to crop plus use the TC or the image is sufficiently large that it exceeds the crop area, and opts for more total pixels

The OP requires to read his post more than once. He's asking about a full frame TC, hence use of TC on his full frame K1. No need of full frame TC with the K3 III, he would be asking for FF TC if it was for using his K3 III crop camera. Some responses in this thread are based on a use case of DFA150-450 with TC on the K3 III, which NOT what the OP asking for a FF TC is about.

---------- Post added 06-06-22 at 19:43 ----------

There is no right or wrong answer, but the issue is if you have only a K1 you need to remember regardless the crop mode is only 16 mp (I.e. like a K5

The OP has both a K1 and K3 III, K1 crop mode is not considered. I responded to the OP and nothing else.

[gatorguy]

While I agree with many of your points, in theory, there are some practical limitations

true to an extent but… I have shot up to ISO25000 at night with the K1MKii you can get some good images even under those trying conditions.
I think the op plans to crop plus use the TC or the image is sufficiently large that it exceeds the crop area, and opts for more total pixels true it is all a trade off, but note that increased magnification, regardless of how achieved means that all the motions can contribute to image blurr not just magnifications before the capture true Shooting with multi point AF while birding is not always what you want. Most times you are looking to shoot only spot focus, because multi point picks up too much foreground, background or other things in the frame

There is no right or wrong answer, but the issue is if you have only a K1 you need to remember regardless the crop mode is only 16 mp (I.e. like a K5) and when birding many times your image is probably only 1 MP because you are shooting from a long way away. It does not matter what mode you shoot, you are usually always cropping, BUT you may not want to shoot crop mode because of the times where you can fill more of the frame so you go for maximum pixels.

The other thing to point out is if I wanted to take your example to extremes, I could argue that we should be shooting with a 50mmF1.4, after all, you just need to crop more. But it does not work that way.

For birding especially, you never seem to have enough length, and there is some benefit in increasing the pixel count of an image by 2,

We are talking about the difference between a record shot vs nothing, or being able to identify what you see, vs not. This is not a discussion about making the absolute best sharpest image for publication, it is about getting an image at all.

I see many people insist on staying at ISO 100 and moan about noise, if they push their iso, but then complain that all their shots are blurry or they can’t take a shot because they would have to push the iso up, I would rather have a sharp shot with a little noise than no shot but that’s just me. Everyone can make their own choice

Excellent explanations throughout Lowell.

[Oldbayrunner]

Try this. Comprehensive Pentax Lens Guide - Gear Guides | PentaxForums.com

All currently-available Pentax lenses are members of the following series:

DA (digital, APS-C crop format);
DA L (affordable digital kit);
D FA (full-frame, digital optimized); and
FA (full-frame, film-era) series.

Try this from 2021 AF Listing instead of one from 2016. Besides what's you point in relation to the topic at hand regarding TC's.

HD PENTAX-DA AF REAR CONVERTER 1.4X AW / Converter / AF Lens Adapter / K-mount Lenses / Lenses / Products | RICOH IMAGING

---------- Post added 06-06-22 at 03:43 PM ----------

If you use crop mode instead of using a TC on full frame, you have several advantages:
1) no vignette
2) no loss of light, makes auto-focus more responsive.
3) faster shutter speed (freezes motion, reduces shutter shock/mirror blur) or lower ISO (less noise)
4) faster burst rate on the K1 ( 7 FPS in crop mode instead of 4 FPS full frame)
5) in crop mode or crop camera , AF points almost cover the entire frame, = better for auto-focus tracking. On full frame + TC , AF points coverage is only in the center of the frame.

Yes I wholeheartedly agree... This is also one of my reasoning for parting ways with my apsc equipment. I don't mind 15 0r 16mp crop images when I need more reach and I don't have to carry twice the equipment.

[slartibartfast01]

Try this from 2021 AF Listing instead of one from 2016. Besides what's you point in relation to the topic at hand regarding TC's.

HD PENTAX-DA AF REAR CONVERTER 1.4X AW / Converter / AF Lens Adapter / K-mount Lenses / Lenses / Products | RICOH IMAGING[COLOR="Silver"]

The link you provide states the TC is for APS-C or am I missing something?

[swanlefitte]

Try this from 2021 AF Listing instead of one from 2016. Besides what's you point in relation to the topic at hand regarding TC's.

HD PENTAX-DA AF REAR CONVERTER 1.4X AW / Converter / AF Lens Adapter / K-mount Lenses / Lenses / Products | RICOH IMAGING[COLOR="Silver"]

this part? *When this converter is mounted between a 35mm full-frame SLR camera body and a D FA-series lens, the image size is automatically cropped to the APS-C format.

[biz-engineer]

The other thing to point out is if I wanted to take your example to extremes, I could argue that we should be shooting with a 50mmF1.4, after all, you just need to crop more. But it does not work that way.

If you take any reasoning to the extreme, any reasoning will eventually fail. In my post, I'm talking about five years of practical experience in the field (national park) birding and wildlife, with Pentax K3, Pentax K1, DFA150-450 with and without HD DA TC, and the actual photographic results that led my choices, based on real life use and actual images. Practice is good, better than wanting to hold a position on beliefs. Now, I've given my 5 points conclusion based on years of practice, hoping it could save time and money to someone asking about the value of a full frame TC. You are free to consider my experience or not, and just go thru you own trial & errors.

[swanlefitte]

Besides what's you point in relation to the topic at hand regarding TC's.

Kind of disingenuous when you said this.

.Prove me wrong show us anywhere specifying a Pentax teleconverter is designated for strictly Apsc lens' .

[Oldbayrunner]

Well, Never being afraid to admit when I am wrong I have to regarding my posts in this thread. I only looked at the present Pentax teleconverters being for K mount and able to work with full frame K1's not noticing that they are indeed as shown considered Apsc teleconverters. So I stand humbly corrected....

[hatsofe]

I have been waiting for a rumoured modern Pentax full frame teleconverter for years. It seemed like such an obvious addition to the FF lineup. But nothing. Has anyone heard anything lately?

I guess I will finally bite the bullet and get the DA 1.4x, as I mostly use the K3iii these days for telephoto work, and it appears to mesh well with the DFA 150-450. I don't have a long prime, but could also use it with the DFA* 70-200 on APS-C. Or should I wait longer?

Pentax 150-450mm works nicely with 1.4x-L convertor; manual focusing only , of course. The installation is possible only if the tele-zoom is extended beyond 300mm. Excellent image quality in most cases. I have no problem hand holding it mounted on my pistol grip, and with shutter speed as slow as 1/1000 sec. The magnification is so considerable, that I start thinking of getting a full frame K-1. I shoot birds mostly and there are two major problems with this set-up: the narrow angle of view (hard to find an object through the OVF after spotting it with an eye) and a reduced light (about 1.5 stops I estimate).
Common tern | Hatsofe B | Flickr
Glossy ibis | with a dead fish | Hatsofe B | Flickr

[clackers]

I shoot full frame a lot, and shoot with the DA converter on it a lot.

Of course, the actual corners aren't usable, which would be a problem for landscape photography.

Not for sports or wildlife, because to us, no lens is long enough. We're always dreaming of filling the frame, and can't get close enough, we always crop, so vignetting is pretty much irrelevant.

Picture quality is great with the HD TC.

The pics below are it in conjuction with the F*300 f4.5

[mikesbike]

I love my K-1 II, but have no intention of using it for long tele- for that I am with biz, I'd go to the K-3 III if I had one, but will go to my likewise excellent KP, which is far easier than my K-1 II for transporting. That has been my plan right along, APS-C when needing easier carrying, especially for tele use.

But if had only my K-1 II, I'd have no problem using the TC as it is designed- in APS-C crop mode. If it is possible to use this TC with my K-1 II in FF mode, I'd simply crop out the dark corners, which might not be as much of a crop as shooting in APS-C crop mode.

As it is, I have yet to acquire the excellent DA 1.4x TC. I have the old FF Tamron AF 1.4 TC which is well regarded. I've only used it with my old screw-driven FA* 300mm f/4.5 on APS-C cameras where it has performed well. I also have the DA* 200mm f/2.8 and have not tried the Tamron TC with it and do wonder if it would AF with this SDM lens. If it does not, I might possibly go for the DA HD TC, which not only performs fine optically, but with the FA* 200mm, it could save me from carrying more gear by using the TC rather than adding the FA 300mm along with the DA* 200mm, though if carrying is not an issue, using both would be best, with or without the TC.

---------- Post added 06-07-22 at 10:37 PM ----------

I shoot full frame a lot, and shoot with the DA converter on it a lot.

Of course, the actual corners aren't usable, which would be a problem for landscape photography.

Not for sports or wildlife, because to us, no lens is long enough. We're always dreaming of filling the frame, and can't get close enough, we always crop, so vignetting is pretty much irrelevant.

Picture quality is great with the HD TC.

The pics below are it in conjuction with the F*300 f4.5

Very nice shots, and a great demo as to the quality of this TC.

[swanlefitte]

We're always dreaming of filling the frame, and can't get close enough, we always crop, so vignetting is pretty much irrelevant.

So true. It is a herculean task. I looked at a calculator to put that into numbers.
With a FF camera and a 300mm lens at 2 meters the vertical is estimated around 136mm(160 at infinity focus) and a bird is close to 50mm so you still only have 1/3 of the frame IF you don't have breathing in your lens. Getting as close as 2 meters away is almost impossible.
with 420mm best estimate is still 90.3mm(114mm at infinity focus) but I can also stand 2.7 meters away and still get a vertical of 130mm(154mm at infinity focus) This gives me a much better chance of being far enough away that the bird doesn't startle.

But also look at noise. I get to either use 1.4x the number of pixels or I get to use less with each pixel having 1.4x more light. Viewed at the same size neither will show more noise than the other. If I view each at 100% the bigger photo will have more noise but only because it is bigger.

edit: I wondered about the angle of view estimate so I tested it out with my set up, the ks-2 55-300 at 260mm and the 1.4x tc. at about 2.7 meters my angle of view was close to the number given by the calculator but between that number and infinity focus. The tc didn't have any change. It was 1.4x magnified in the photo.

I used this tool. It notes close distance calculations are approximate see notes at site. https://www.pointsinfocus.com/tools/depth-of-field-and-equivalent-lens-calculator/#{%22c%22:[{%22f%22:13,%22av%22:%228%22,%22fl%22:50,%22d%22:3048,%22cm%22:%220%22}],%22m%22:0}

[Ian Stuart Forsyth]

Not for sports or wildlife, because to us, no lens is long enough. We're always dreaming of filling the frame, and can't get close enough, we always crop, so vignetting is pretty much irrelevant.

One of the reasons why I use a TC is to that I don't need to crop