Old lens, new camera

[phseven]

Hi all! New here and registered because I kept finding great advice from members when I googled different topics. I'm hoping some of your wiser heads can help me out.

I have a Nikon D3100 which I bought just over 6 months ago with a Tamron 18-200mm f3.5-6.3 lens. I love the camera and this lens covers most of my needs at the moment. I'm very much a hobbyist and don't have huge amounts of money to spend (already maxed the budget on what I have, though made a little back by selling the kit lens which came with the camera).

Here's my dilemma: I occasionally like to do some very long-range shooting (certain candid work, etc.) and will be off to the F1 Barcelona Grand Prix in May. The reach of my lens at 200mm just isn't enough for these occasions but I have virtually zero budget so another lens at the moment just isn't an option. Full zoom and significant crop with this lens is very soft and especially as I will probably have to bump the ISO to catch those F1 cars flying past.

Two possible solutions:

1) Spend 60-120euros (almost certainly not the upper end) on a Vivitar 2x converter for my current lens. I believe the aperture control will still work but I may lose autofocus? Is the quality actually going to be any good at the effective 400mm or will it just be very soft and very dark?

2) I have some old kit from my days as a B&W film photography student. However, it is all Pentax mount. The gear includes a Tamron 70-210mm f2.8 (?) which I loved back then and a 2x converter which working brilliantly with it to make a 140-420mm f5.6. I could purchase, for around 20-30euros, a mount converter to use these two on my Nikon D3100 but have no idea what the results would be like. Also, as my Nikon D3100 is DX format, does that mean the Tamron would be subject to a 1.5x sensor effect, creating a 200-600mm lens? If so it's very attractive as a budget solution.

I suppose for 30euros I don't have much to lose but don't want to spend it then find it's rubbish and have to buy the 2x Vivitar for my new Tamron lens, then find out that's rubbish aswell!

I know what you pay is generally what you get and that I won't get perfect pictures for little money, however, This Grand Prix is perhaps a once-in-a-lifetime for me and I want to get the best I can with what I can afford.

All suggestions extremely welcome. Please help me out of this confusion!

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[Patrice]

Adding a 2x converter of questionable quality to an already marginal lens will not do you any favors. An exercise in frustration. I know what I'm about to suggest might be derisive to some but for your budget you should be able to find a nikon 500mm f8 catadioptric lens.

I don't know of any pentax to nikon adapters. Maybe some of the other members know of some. If there are any, they might be on the expensive side because they will likely have some glass elements in then because the flange to focal plane distance is longer on a nikon than on an old pentax.

[djacobox372]

I wouldn't recommend that combination. I've used the Tamron 70-210 f2.8 af (nikon mount) on my nikon d200--it was a great lens, although it was soft wide open and had pretty bad CA both of which became much worse when using a teleconverter.

My guess is that the adapt-all mount version of this lens is an even less stellar performer.

I don't think you'll find much in your price range, the best you could probably do optically for less then $200usd would be a nikon 300mm f4.5 prime ai lens. Excellent optics and can be used with a 1.4 teleconverter to make it a 400mm f6.3 (600mm when you factor in the crop). Of course this will not meter with a D3100, but that isn't that big of deal when shooting in consistent lighting conditions.

You'll find that prime lenses are much sharper then zooms.

There are two versions of this lens, the IF ED version is probably out of your budget (around $325usd used), but the non-ed version is also excellent, and was very popular so there are a lot available for less then $200usd. It's a well built all metal lens, so don't mind if it's rough looking as long as the glass and aperture is in good shape.

[nick_cool]

I really like VR when hand holding the camera at 150mm or more. There is a very inexpensive Nikon 55-200 mm VR, and some 300mm Nikon zooms not very expensive.

I use to have a 28-200mm Tamron, it was k for me, but my current Nikon 18-110mm VR is much better.

[phseven]

Thanks for the quick replies! Sounds like my ideas are pretty rubbish then?

djacobox: is this the lens to which you are referring? Nikon NIKKOR 300mm f/4.5 | eBay

Patrice: the PK to AF converter I've seen is this pentax PK Lens To Nikon adapter D3x D300 D5000 D90 D60 - eBay (item 120592942486 end time May-03-11 00:13:23 PDT) but I've no idea if it's any good. Would it worthwhile risking the 25euros to use the tamron lens and 2x adapter on my D3100 or are they just not worth bothering with?

Also, the 500mm f8 you referred to, is it this? Nikon Reflex-Nikkor 500mm f/8 Mirror Tele

and how does something like this stand up to scrutiny compared with my current zoom plus a 2x teleconverter? Clubman 500mm f/8 Mirror Lens For Nikon. Excellent Cond - eBay (item 170625275496 end time Apr-16-11 12:50:12 PDT)

Sorry to put loads of links but I'm not familiar enough with different lenses to be certain that what you are describing and what I'm looking are the same thing!

nick_cool: thanks for the advice but ay of the VR lenses, new or old, seem to be way out of my budget right now.