[noelpolar]

Hi......I've just bought a F* 300 4.5 and I was looking to also get a 1.4 or 1.7 TC that will work with it and give the least drop in IQ. Would really appreciate anyone who has had this lense letting me know what worked best for them. Also if it worked ok with other FA lenses such as a 77. Thanks

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Last edited by noelpolar; 04-20-2014 at 06:06 AM.

[goubejp]

I use the new Pentax 1,4 TC with the FA*300f2.8, and it works fine. It should do fine with the FA*f4.5 IMO

[Ole]

I've used the new DA 1.4x with the FA*300/4.5 and the 77/1.8 with excellent results. Our in-depth review should be published soon.

[snostorm]

Hi noelpolar,

First congrats on obtaining a great lens!! I chose the FA* 300/4.5 for my own reasons (I prefer the hood and also the MF/AF switching on the FA* version + I already had a tripod ring that would work with it),

I think the suggestions for the new Pentax AW 1.3x TC are a bit of overkill for a screw drive lens. As fas as I can tell, the optics aren't vastly superior to the good screw drive 1.4x TCs that have been available for years (Tamron F 1.4x AF PZ MC4, Sigma EX 1.4x APO, both discontinued, or the Vivitar 1.4x which is available new) The only advantage that the Pentax would have is the chip will report the correct FL and Av, which might be important for your use, but this never has been much of a problem for me in practical use. For SR, the difference between 300 and 420 is not that great, and I still can reliably gain about 2 stops of shutter speed for handholding. If they all were the same price, and I had also had an SDM lens that I wanted to use the TC with and retain AF, then it'd be a no brainer, but at $600, and with no SDM long tele lenses, I decided to pass. If I want a 420mm f6.3, I'll use the Tamron or Sigma 1.4x TCs already mentioned and get what I'd expect to be similar performance. Ron (brandrx on DPR) long recognized as the TC guru on that forum, came to the same conclusion after obtaining a 1.4x AW soon after they were released.

Personally, I use my FA* 300/4.5 (essentially the same lens optically as the F*, but with some physical and operational differences) with a Pentax F 1.7x Auto Focusing Adapter as my main birding combination to get a very portable AF 510mm f7.7 for birding. It's very compact and handholdable. At f7.7 max aperture, it sounds like the AF would be sketchy, and it would only AF in bright light, but AF is really not a problem until it gets pretty dim, and available shutter speeds without using pretty high ISO become a more limiting factor than AF performance for me. The reason why AF can work with this combination is that the AFA with a tele lens has a limited focusing range, and the lens needs to be manually prefocused to allow the AFA to take over the focusing chores. The negative is that you need to manually adjust the focus ring if you're shooting at significantly different distances from shot to shot -- a lot of people don't like this.

The positives are that the AFA works as a focus limiter, so in tricky situations where the AF system might want to lock on the wrong thing in the AF sensor's area, I can refocus by slightly shifting the aiming point and rely use AF to refocus quickly without worrying about losing the shot altogether because the AF system decides to do a frustrating and time consuming full lock to lock hunt. The second plus is that AF will lock reliably even with the slow max aperture and relatively low light. The reason it works is that I have to manually prefocus the lens. In low light, the AF system will normally hunt and not achieve lock with most slow lenses, but if one manually prefocuses the lens so it's anywhere near the correct focusing distance, the system usually has no problem acquiring a lock. With the AFA the manual prefocus is part of the process. I actuate AF, then manually focus the lens. When the prefocus is close enough, the AFA takes over automatically, and it achieves a lock so I can take the shot. The prefocus needs to be closer in lower light, but the process remains the same, so although I'm not aware of it, I actually continue the manual focusing until the AF system can take over. I'm sure this sounds more complicated than it actually is. Another positive is that with the AFA, no FL is reported to the camera body, so the body requests a FL be inputted for SR. The setting is assigned to the AFA, so SR assumes the same setting every time the AFA is mounted. If you use it with another lens, then you need to input the correct FL for that lens, but if you use it only with one lens, the correct setting will be remembered.

If you want to shoot subjects that are moving through a wide range of focusing distances, then the AFA will probably disappoint, and a full focusing range TC would be a better choice. From what I've seen, the Promaster 1.7x seems to perform very well optically at the same magnification, but the max aperture might be a limitation in lower light for AF performance. The 1.4x TCs would probably be a better choice for this kind of work anyway.

Optically, I'm very pleased with the performance of the 1.7x AFA. Here are a few examples:

With the K-5, FA* 300 f4.5 + 1.7x AFA. Slightly cropped on the sides and PP'd to taste. This was shot handheld


With the K-5, Canon FD 300 f4L (permanently converted to K mount) + 1.7x AFA. Slightly cropped on the sides and PP'd to taste. This was shot at ISO 1600 in a shaded area -- tripod mounted



Scott

[seadog]

I use my K-5 with the F*300 and Promaster 1.7 and am very happy with the results. I would not use the AFA 1.7 with that lens cuz there is no full-time manual focusing. You would constantly be shifting from AF to MF, both on the lens AND on the body, and then back again each time the limited AF zone on the AFA was exceeded. It is a bit of a pain as it is with the PM 1.7 When I want to reset the focus into the distance to prevent full-racking (so as not to scare away birds)
In tests with two different AFA 1.7s I found the PM 1.7 was noticeably sharper.

[snostorm]

I use my K-5 with the F*300 and Promaster 1.7 and am very happy with the results. I would not use the AFA 1.7 with that lens cuz there is no full-time manual focusing. You would constantly be shifting from AF to MF, both on the lens AND on the body, and then back again each time the limited AF zone on the AFA was exceeded. It is a bit of a pain as it is with the PM 1.7 When I want to reset the focus into the distance to prevent full-racking (so as not to scare away birds)
In tests with two different AFA 1.7s I found the PM 1.7 was noticeably sharper.

Hi seadog,

Sorry seadog, but you're passing incorrect information here. Any lens AF or MF, is a full time MF lens on the AFA since there is no pass through screw drive shaft in it. With the F* 300/4.5 (or any other lens for that matter), you do not have to switch the body to MF to manually focus the lens with the AFA if the distance is out of range because the lens' AF mechanism is not connected to the body. You do have to switch both the lens and the body to MF in the F* 300/4.5 to manually focus without turning the internal AF motor in the body when using the Promaster, but not with the AFA, where you only have to engage the focus clutch, which connects the focus ring to the focusing helicoid in the lens. I'd consider this a negative aspect of the Promaster combination in comparison. I don't manually tweak focus with the AFA after it achieves lock. If I have to refocus, I do it by moving the camera to give the AF system something better on the subject to lock onto, then use AF to refocus, without fearing a full lock hunt, and I can repeat this if necessary. In this respect, I find the limited focus range a significant benefit -- just like having a focus limiter as on my FA* 300/2.8, but even easier to use.

Another point is that I've never had sound from the screw drive AF scare birds away in over 9 years and tens of thousands of bird shots, even as close as 8-10 feet -- they don't seem to notice. It might be because I live and shoot in a large urban area, and they are used to mechanical sounds. . .or that people who have experienced this were using lenses that didn't focus internally, so the front element of the lens rotated when focusing. In this case, the motion was probably what alarmed the birds, but the shooter assumed it was the sound. In any case, the AFA focuses internally, and the focus throw is very short compared to just about any lens, so the sound is very brief, and not as loud as most lenses because there's less stress on the motor moving the physically small and light focusing lens group. This is another advantage of the AFA, BTW, AF is very fast, faster than the lens alone, even with the older bodies.Of course, this is offset by the need to MF to within range, but after a few hundred shots initially, this should become second nature and really isn't as much of a problem as it might seem.

Another advantage to the AFA I would think would be for SR. The Promaster or any screw drive AF TC also passes through the information stored on the lens chip straight to the body. This includes FL, and none of the AF TCs before the Pentax 1.4x AW that was recently released automatically does the FL or Av conversions for the lens. So FL remains 300mm as opposed to 510mm, and Av would always be faster by a factor of 1.7. With the AFA, one needs to input the FL because the AFA does not have a "data" pin on the lens side, so it cannot pass through the FL of the lens, and Av is automatically converted using a 1.7x multiplier so the Av shown in the VF and on the exif is at least close to correct (the AFA does round the value up in some cases).

As far as sharpness between the two, I can't say. I've never used the Promaster 1.7x, and I hear it's a good TC from trusted associates, so that's why I suggested it. It could very well perform a bit better optically, but I'd have to see some side by side examples to be convinced. I don't think there's a lot of room for the Promaster to be noticeably sharper, but it is decades newer, and lens coating differences could give better contrast which could make the images look sharper. . . Regardless, I wouldn't switch. The tradeoff between a very minor IQ boost and significant disadvantages working with it in the field for me would not be worth it. I like the advantages in using the AFA, and minor differences in IQ can be compensated for in PP. I think the examples posted here and in other posts over the years bear this out.

Scott

[noelpolar]

I use the new Pentax 1,4 TC with the FA*300f2.8, and it works fine. It should do fine with the FA*f4.5 IMO

Thanks....this is probally the default one at the moment.......expensive though.

---------- Post added 04-21-14 at 09:06 PM ----------

I've used the new DA 1.4x with the FA*300/4.5 and the 77/1.8 with excellent results. Our in-depth review should be published soon.

Thankyou for the heads up.......do you know if it would work on FF if it ever happens? ie no vignetting

(I'm sending out positive vibes for a "K3ish" based 36mp ff for $2,100 to be released later in the year)

---------- Post added 04-21-14 at 09:09 PM ----------

I use my K-5 with the F*300 and Promaster 1.7 and am very happy with the results. I would not use the AFA 1.7 with that lens cuz there is no full-time manual focusing. You would constantly be shifting from AF to MF, both on the lens AND on the body, and then back again each time the limited AF zone on the AFA was exceeded. It is a bit of a pain as it is with the PM 1.7 When I want to reset the focus into the distance to prevent full-racking (so as not to scare away birds)
In tests with two different AFA 1.7s I found the PM 1.7 was noticeably sharper.

.

I've been looking at your shots and they are great.....will look at the promaster 1.7 for sure!

---------- Post added 04-21-14 at 09:13 PM ----------

Hi seadog,

Sorry seadog, but you're passing incorrect information here. Any lens AF or MF, is a full time MF lens on the AFA since there is no pass through screw drive shaft in it. With the F* 300/4.5 (or any other lens for that matter), you do not have to switch the body to MF to manually focus the lens with the AFA if the distance is out of range because the lens' AF mechanism is not connected to the body. You do have to switch both the lens and the body to MF in the F* 300/4.5 to manually focus without turning the internal AF motor in the body when using the Promaster, but not with the AFA, where you only have to engage the focus clutch, which connects the focus ring to the focusing helicoid in the lens. I'd consider this a negative aspect of the Promaster combination in comparison. I don't manually tweak focus with the AFA after it achieves lock. If I have to refocus, I do it by moving the camera to give the AF system something better on the subject to lock onto, then use AF to refocus, without fearing a full lock hunt, and I can repeat this if necessary. In this respect, I find the limited focus range a significant benefit -- just like having a focus limiter as on my FA* 300/2.8, but even easier to use.

Another point is that I've never had sound from the screw drive AF scare birds away in over 9 years and tens of thousands of bird shots, even as close as 8-10 feet -- they don't seem to notice. It might be because I live and shoot in a large urban area, and they are used to mechanical sounds. . .or that people who have experienced this were using lenses that didn't focus internally, so the front element of the lens rotated when focusing. In this case, the motion was probably what alarmed the birds, but the shooter assumed it was the sound. In any case, the AFA focuses internally, and the focus throw is very short compared to just about any lens, so the sound is very brief, and not as loud as most lenses because there's less stress on the motor moving the physically small and light focusing lens group. This is another advantage of the AFA, BTW, AF is very fast, faster than the lens alone, even with the older bodies.Of course, this is offset by the need to MF to within range, but after a few hundred shots initially, this should become second nature and really isn't as much of a problem as it might seem.

Another advantage to the AFA I would think would be for SR. The Promaster or any screw drive AF TC also passes through the information stored on the lens chip straight to the body. This includes FL, and none of the AF TCs before the Pentax 1.4x AW that was recently released automatically does the FL or Av conversions for the lens. So FL remains 300mm as opposed to 510mm, and Av would always be faster by a factor of 1.7. With the AFA, one needs to input the FL because the AFA does not have a "data" pin on the lens side, so it cannot pass through the FL of the lens, and Av is automatically converted using a 1.7x multiplier so the Av shown in the VF and on the exif is at least close to correct (the AFA does round the value up in some cases).

As far as sharpness between the two, I can't say. I've never used the Promaster 1.7x, and I hear it's a good TC from trusted associates, so that's why I suggested it. It could very well perform a bit better optically, but I'd have to see some side by side examples to be convinced. I don't think there's a lot of room for the Promaster to be noticeably sharper, but it is decades newer, and lens coating differences could give better contrast which could make the images look sharper. . . Regardless, I wouldn't switch. The tradeoff between a very minor IQ boost and significant disadvantages working with it in the field for me would not be worth it. I like the advantages in using the AFA, and minor differences in IQ can be compensated for in PP. I think the examples posted here and in other posts over the years bear this out.

Scott

Thankyou for this explanation.......will look inot the AFA as well. Also thanks for all the detail in your 1st post..... most useful!

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Last edited by noelpolar; 04-21-2014 at 04:59 AM.

[seadog]

Ooooops! Thanks Snostorm for correcting my very incorrect post. That will teach me to talk about something I haven't actually tried myself! But I am glad that I got Snostorm to make some more good comments about the use of the AFA. That is very insightful and now I am really looking forward to trying the F*300 with the AFA I just (again) acquired.

I should also state that the tests I did with the AFA and PM 1.7's were on the Tamron SP400 f4 (magnified live-view MF on my K-5). From what I read it seems that results can be very camera/lens/TC specific so my findings don't necessarily reflect how they would compare on the F*300. Also, I will come out of the closet right now and admit that I am a SPP! Yes, I am a Super Pixel Peeper and sometimes even view at 2:1. So unless someone is trying to print real big (or seriously crop) they would never notice what I called a "noticeable " difference between the two. I think the other advantages Snostorm described could make a bigger difference.

I have only been birding a few months now but there have been a number of occasions when the screw drive noise definitely seemed to scare away birds, and I have to say that it seriously bothers me. For me, being out in nature is kinda a meditative experience and I find the full-racking screw drive racket very jarring. I was thinking about trading it for a FA*300 or even splurging for a DA*, but maybe the AFA will solve that problem.
Lance

[Ole]

The DA converter and FF: For what it is worth we saw no visible vignetting in the viewfinder with an FA 20mm lens on a FF film camera, but we didn't shot and develop any film to verify.

[Transit]

excellent explanations from snostorm thanks !
best collected thoughts on the F*300/4.5 + AF TC combo i've seen !
My present negotiations for a nearby AF TC are reinforced
Pete

[mikeSF]

that is a great lens, i love mine so much!
I use the Tamron pz AF 1.4x TC with it and it works beautifully.