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04-01-2007, 07:28 AM   #1
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1.4 vs 1.7 vs 2.x Convertors

Hi all

I am new to DSLR and you see from my sig the lenses I have. I was wondering what type of converter I could get to increase the range on 300mm ? What do this convertors cost and I assume they are Lens specific (meaning I need to look for one that will fir the Sigma?) - Can I order them online (very few Pentax dealers where I am - got all my supplies at London Drugs so far)

Also for sports photography (Son football) are there any downsides to using these convertors ? I have seen some pretty awsome short in the Gallery of the moon and I was wondering if these convertors are better suited for stills with a tri-pod ?

Enjoying the camera - just gotta spend more time using it .

thx...........dy

04-01-2007, 09:44 AM   #2
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QuoteOriginally posted by daacon Quote
Hi all

I was wondering what type of converter I could get to increase the range on 300mm ? What do this convertors cost and I assume they are Lens specific (meaning I need to look for one that will fir the Sigma?) - Can I order them online (very few Pentax dealers where I am - got all my supplies at London Drugs so far)

Also for sports photography (Son football) are there any downsides to using these convertors ? I have seen some pretty awsome short in the Gallery of the moon and I was wondering if these convertors are better suited for stills with a tri-pod ?
1. There is no free lunch: all teleconverters will reduce the quality of the image. The difference can range from slight to severe. It depends on the specific lens and the specific converter. The best results are with very high quality lenses and a high quality converter specifically matched to the lens. The worst is with lower quality lenses and lower quality converters designed to work with any lens. The higher the magnification, the greater the loss of image quality. With marginal combinations, you need to stop down several stops from the maximum for decent sharpness.

2. All converters cause a loss of light. A 1.4X will cause the loss of one stop of light, a 1.7X one and 1/2 stops, and a 2X will lose two stops. This will give a darker viewfinder image and slower, less reliable auto-focus. Generally, auto-focus is unreliable at slower than f5.6. Since your long lens is already at f5.6, even with a 1.4X converter you will lose reliable auto-focus, since the effective aperture will be f8. It might still AF in bright light, but it will be slow and will hunt. For sports action use where AF speed and a fast shutter speed are essential, it will be useless.

3. Sigma makes high quality, matched teleconverters (the 1.4X and 2X EX DG converters) but they are not compatible with your lens. Your only option will be a generic converter. There are many of these available new and used in both 1.4X and 2X models. There are no current Pentax converters, but the Converter A 1.4X-S and Converter A 2X-S are the best generic ones (the Pentax "L" converters are matched to certain lenses and will not work with your Sigma). The Pentax converters are auto-exposure, but manual focus only.

The only 1.7X converter that I am aware of for the Pentax mount is the (discontinued) Pentax F auto-focus adapter, which allows auto-focus of manual lenses and magnifies the image 1.7 times. These can be found used but the recent prices are quite high (over $300). It does work with auto-focus lenses, but your f5.6 lens will not give reliable AF. Pentax recommends f2.8 or faster.

4. Your Sigma is a decent consumer zoom but it is not a top quality lens and it is quite slow at f5.6. I would not have high expectations of good results with a teleconverter using that lens. Feel free to give it a try if you like. But I wouldn't want to shoot sports photos at f8 or f11, since the background will not be blurred enough and the shutter speed will be too slow.

If it was me, I would save my money and put it towards a longer lens. Something like a Sigma 135-400, 170-500, or 50-500 EX (the "Bigma") will be a more satisfactory solution.
04-01-2007, 09:55 AM   #3
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Thanks Gary

I realize my lenses are not top quality - but again I an new at this and these will suffice until I get better at using the camera. I wanted to get a DLSR , couple of lenses all required accessories (batteries, cards, case) and the fricken taxes ..for under 2k and this set up was well under. I can see this can be an expensive habbit for sure.

I was looking for a free lunch - you were right haha- my head already had your answer my heart was hoping for a $150 fix These generic telconvretors might be ok for stills - sports not so much.

I will saving my pennies for the Bigma or the 170-500 that looks cool off the the review sites .....

Thanks again.
04-01-2007, 09:57 AM   #4
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Hi Daacon,

I second everything that GaryML said about converters. I am using the Promaster 1.7 Auto Teleconverter with the Tamron 28 -300 XL lens, and it looks remarkably like the Pentax 1.7 teleconverter! The results have not been as good as I would like. So I gave up on using it on autofocus because I could manually focus the lens faster and more accurately.

I was attempting to shoot some of my grandson basketball games with the Teleconverter, and I found that I was far better off using an old Pentax 135mm 2.5 telephoto lens that I used with my old reliable Pentax Super Program film camera. With a decent post processing program this lens did a far better job than the Tamron 28 - 300 did.

Good Luck,
Bill

04-01-2007, 10:12 AM   #5
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Hi Wipearl

I will have to wait for Grandkids and basketball (ahhh I did not say that !) My daughter played all through school up to this year (senior in High School). I used various PS for those days- of the 40 or 50 shots I took in a game 5- 10 worthwhile - wish I had this camera then - (some of those gymnasiums the lightling was brutal!).

Anyway my Son is only a freshman this year - so hopefully two more years of Football action - I got some good shots last season borrowing a friends Rebel - which more or less convinced me to go down this DSLR road ....

thx........dy
04-01-2007, 11:40 AM   #6
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I got my K100D last September, just in time for my sons football season. He's just in the 4th grade, so the speed may be slower, but the technique is still the same. Thankfully, we have good weather and all our games were daytime games. I just used my Tamron 28-300 lens for all my shooting. I could post some later, if interested, but my experience was:

1. putting any TV on the lens slowed the AF to a point where it was unacceptable for me. The best I could do was to prefocus on a spot and hope.
2. My lens gave me the reach I needed, but I don't think it could have held up to low light at night. I have used it at 1600 and 3200 ISO indoors for basketball and, for a fathers photo collection, got some good shots.

My advice:

If you have loads of cash, buy one of those fast new lenses coming out. Or, just crank up the ISO and go to 300mm and have fun. I would say that the quality I get at 3200 ISO would be good for a newspaer, but not good for a blown up poster. For 4x6 with some retouching and noise reduction, it is also quite good.

I think if you look at threads started by me, back in October, you will find some football shots. Look in the January/Feb timeframe and you will find some basketball. There is also some indoor swim/water polo/synchro shots in there somewhere. But, now it is baseball season, so I have to retrain myself at what to anticipate for good shots.

Jeff

Last edited by jsundin; 04-01-2007 at 11:24 PM. Reason: fix some typos
04-01-2007, 12:39 PM   #7
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Thanks Jeff

So you are suggesting ISO 3200 ? Which new lenses are you talking about the DS* ones ? Loads of cash hahaha - I suppose I could sell the sigma 70-300 and pay for some of it. I think really 300mm would be ok as usaully they let the parents with cameras get pretty close to the sidelines.

Did you use AV , TV or Manual ? any settings you prefered ? Weather can be an issue for sure - we had a copule games in overcast and rain/snow a few games under the 'lights' (night games) and the rest were pretty Sunny Days.

I will likley go out and pratice on other games to be prepared for my Son's games. Football pretty big here between the high schools and community leagure play games everyday somwhere from August - Novemeber.

thx........dy
04-01-2007, 01:17 PM   #8
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I can tell you right away that if you want to lose as little IQ as possible, go for the Pentax teleconverters.

Here is a 100% crop of my neighbor's old TV antenna that was 150 feet away from me. It's shot at 700mm (K 500mm + 1.4x-L).



I still can't believe this stunning result myself..


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04-01-2007, 01:25 PM   #9
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Mo

Wow that is stunning you can see the threads for pete's sake ! 150 Feet sure that was not inches ! So what is the model number of that lens and how many barrels of cash does taht cost ?

That detail and clarity is impressive would be good for 'line shots' before the ball is snapped - still wonder on action , following the play and snapping the shutter how it would fair.
04-01-2007, 02:21 PM   #10
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here's a quick test i posted with the M200 + 2x tamron. these are full size shots taken at f8 with flash. they are all around 1meg. i think it's a good match. the 2x-s should produce better than this.
200

posted in wrong thread.
04-01-2007, 03:29 PM   #11
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QuoteOriginally posted by daacon Quote
Mo

Wow that is stunning you can see the threads for pete's sake ! 150 Feet sure that was not inches ! So what is the model number of that lens and how many barrels of cash does taht cost ?

That detail and clarity is impressive would be good for 'line shots' before the ball is snapped - still wonder on action , following the play and snapping the shutter how it would fair.
Yup, it was 150 feet accross from my back yar. The lens's minmum focusing distance is a whooping 30 feet, lol. Here's the original thread with more pics: https://www.pentaxforums.com/forums/post-your-photos/4269-my-sharpest-700mm-tele-shots.html

The lens is actually reasonably priced- I bought my mint copy for $500 from KEH last year.


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04-01-2007, 04:50 PM   #12
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here's a shot with the same lens as MOs except with a tamron mc4 2x that cost me all of $10 delivered. this 2x usally goes for around 50usd before shipping. i have the same shot with just the 500mm if you are interested.
oh, this was shot from 110meters out.

04-01-2007, 05:12 PM   #13
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Wow, stunning heron shot from 500 feet Adam!

Each February I'm challenged by some eagles across the Connecticut River from Essex. They come downstream for the winter to where the water is too salty to freeze. The distance is about 2600 feet. Last year I used a Coolpix on a 480mm f6 telescope, this year my K100D on the same scope. Well.... you can tell it is an eagle with white head and brown body. A few frames show a dot of orange for the beak. To do any better I think I'd need a multi-thousand dollar lens instead of a $400 telescope. Your results made me think perhaps next year I'll bring my 2x Barlow Lens (that's astro-speak for teleconverter). It would make my scope 960 mm f12 but on a bright day it might work.
04-01-2007, 09:11 PM   #14
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Thanks everyone - looks like I will be on the lookout for the 500mm and for another $50 or so gotta give the convertor a try anyway - some impressive shots for sure .

Would it be advantageous to wait for the DS* Lens ? would they be of any benfit on a K100D body ? Will there be a ds* at 500mm ? (Focus time in any sports scene where any additional speed would help!)

thx.........dy
04-01-2007, 11:26 PM   #15
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I'm not recommending ISO3200 as a general course of action. I found that in the case of getting the shot at 3200, versus missing it entirely, I opt for the noisy shot every time. If you can roam the sidelines, I think 300 is plenty. You may also want to think about something that can capture sideline shots of the kids coming off the field, their expressions, etc. I'll dig up some samples for you this week.

Jeff
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